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The Magazine of the Arnold ArboretumV O L U M E 6 6 N U M B E R 4

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Arnoldia (ISSN 00042633; USPS 866100)

is published quarterl b the Arnold Arboretum

o Harvard Universit. Periodicals postage paid

at Boston, Massachusetts.

Subscriptions are $20.00 per calendar ear

domestic, $25.00 oreign, paable in advance.

Remittances ma be made in U.S. dollars, b

check drawn on a U.S. bank; b internationalmone order; or b Visa, Mastercard, or Ameri-

can Express. Send orders, remittances, requests to

purchase back issues, change-o-address notices,

and all other subscription-related communica-

tions to Circulation Manager,Arnoldia, Arnold

Arboretum, 125 Arborwa, Boston, MA 02130-

3500. Telephone 617.524.1718; ax 617.524.1418;

e-mail [email protected].

Arnold Arboretum members receive a subscrip-

tion toArnoldia as a membership benet. To

become a member or receive more inormation,

please call Wend Krauss at 617.384.5766 or

email [email protected].

Postmaster: Send address changes to

Arnoldia Circulation Manager

The Arnold Arboretum

125 Arborwa

Boston, MA 021303500

Nanc Rose, Editor

And Winther, Designer

Editorial Committee

Peter Del Tredici

Michael S. DosmannJianhua Li

Richard Schulho

Copright 2009. The President andFellows o Harvard College

Contents

2 th Pril ad Pial f Buru

Keith Woeste and Paula M. Pijut

13 A Clr Lk a Fugi i h ArldArbrum

Kathryn Richardson

22 Amrica Chu i h 21 CurySandra L. Anagnostakis

32 Bk Rviw:Amrcan Chtnt: Th Lf,Dath, and Rbrth of a Prfct Tr

Heather D. Heimarck

34 2008 Wahr a h Arbrum

36 Japa Clhra: A Hidd Gm

Richard Schulhof

Front cover: Fungi eature prominentl in this issue,

which includes curatorial assistant Kathrn Richard-

sons article on Arboretum ungi. Turn to page 15 to read

about this pheasants-back polpore growing rom an old

cucumbertree magnolia (Magnolia acuminata, accession

15154-E) near the Arborwa Gate. Photo b Nanc Rose.

Inside front cover: April 22, 2008: A ne da or a

bumblebee to visit the dangling ellow fowers o

Corylopsis sinensis var.glandulifera. Month-b-month

details o weather at the Arboretum are eatured in the

2008 weather summar. Photo b Nanc Rose.

Inside back cover: Deput director Richard Schulho

proles one o the Arboretums hidden gems, an impres-sive specimen o Japanese clethra (Clethra barbinervis)

accessioned in 1886. Photo b Richard Schulho.

Back cover: When Charles Faxon drew this illustration

o butternut (Juglans cinerea) or C. S. Sargents Silva of

North America (volumes published rom 1891 to 1902),

butternut canker disease had not arrived. Researchers

Keith Woeste and Paula M. Pijut describe butternuts

current state in their article.

Th Maazn of th Arnold Arbortm

VOLUME 66 NUMBER 4 2009

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Butternut (Juglans cinerea), alsoknown as white walnut because oits light-colored wood, is a short-

lived, small- to medium-sized tree (40 to60 eet [12 to 18 meters] tall; 30 to 50 eet[9 to 15 meters] crown spread) (Fig. 1). But-ternuts native range includes most o thenortheastern United States and southern

Canada rom New Brunswick to Georgia,and west to Arkansas and Minnesota (Rink1990; Dirr 1998) (Fig. 2). Butternut otengrows in widel scattered clusters, witheach cluster containing a ew individualtrees. It was never a highl abundant spe-cies (Schultz 2003), but or reasons thatwill be described later, it is even less com-mon now than beore. The ormer preva-lence oand appreciation orbutternutin the landscape is refected evocativelb the man Butternut Hills, Butternut

Creeks, and Butternut Lakes ound acrossthe eastern United States.

Butternut is a member o the walnutamil (Juglandaceae), which includesman amiliar nut trees including east-ern black walnut (Juglans nigra), Persianor English walnut (J. regia), pecan (Carya

illinoinensis), and all the hickories (Caryaspp.). How butternut relates to the otherwalnuts remains a puzzle. Earl taxonomplaced butternut in its own section within

Juglans (Trachycaryon), but more recent treat-ments place it with Japanese walnut (J. ailanti-folia) and Manchurian walnut (J. mandshurica)in section Cardiocaryon (Manning 1978; Fjell-strom and Partt 1994), or with the New Worldwalnuts (Rhysocaryon) (Aradha et al. 2007).Butternut cannot hbridize with eastern blackwalnut, but it can hbridize with Persian walnutto orm J. quadrangulata, and with Japanesewalnut to orm J. bixbyi (USDA-NRCS 2004).O all the walnuts, butternut is considered to be

one o the most winter-hard, to USDA Zone 3(average annual minimum temperature -30 to-40F [-34 to -40C]).

Food, Furniture, and Forage

Butternut has a long histor o useulness.Native Americans extracted oil rom thecrushed nuts b boiling them in water, madesrup rom the sap (Goodell 1984), and threwbutternut bark (which contains toxins) intosmall streams to stun and capture sh. The

The Peril and Potential of Butternut

Keith Woeste and Paula M. Pijut

Figure 1. Researchers collect samples rom a true butternut growing inDaniel Boone National Forest, Kentuck.

AMyROSS-DAVIS

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Butternut 3

taught earl European settlers how to makemedicine rom butternut bark, roots, and husks(Johnson 1884; Krochmal and Krochmal 1982).The inner bark o butternut and its nut hulls

can be used to produce a ellow-brown de.This de was used most notabl on some o theConederate Arms Civil War uniorms, giv-ing rise to the practice o reerring to southerntroops and their smpathizers as butternuts(Peattie 1950).

Butternut is valued economicall and eco-logicall toda or its wood and edible nuts(Ostr and Pijut 2000) (Fig. 3). The sweet, oil,edible nuts are used in baked goods and are alsopopular or making maple-butternut cand.

Butternuts were oten planted near homes onarmsteads or the use o the nuts. There hasbeen limited selection o butternuts or nutqualit and production (McDaniel 1981; Good-ell 1984; Miliken and Stean 1989; Miliken etal. 1990; Ostr and Pijut 2000), but a ew but-ternut cultivars with large nut size and superiorease o cracking (e.g., Chamberlin and Crax-ez) have been propagated, and some o theseare available rom commercial nurseries.

The nuts are also an important ood sourceor wildlie. In orests, butternut trees produce

seed at about 20 ears o age, with good seedcrops occurring ever two to three ears (Rink

1990). Open-grown trees, which benet rommore sun and less competition, can begin bear-ing as earl as ve ears o age and bear annu-all under ideal conditions.

The sapwood o butternut is light tan tonearl white and the heartwood is light brown(Fig. 4). The wood is moderatel hard, but work-able; it saws and carves easil, nishes well,and resembles black walnut when stained. Thecommercial availabilit o butternut wood isnow extremel limited, but qualit butternutFigure 2. The native range o butternut.

Figure 3. Butternut ruits have thick husks covered withstick glandular hairs. Inside the husk is an edible nutenclosed in a thick, hard shell that is elaborated with eight

prominent ridges (Brinkman 1974; Flora o North AmericaEditorial Committee 1993+).

Figure 4. Butternut wood samples: (clockwise rom upper let)bark, slab-sawn, quarter-sawn, and cross-section (note darkerbrown heartwood). From the Ralph F. Perr wood collectionat the Arnold Arboretum.

BILLCOOK,MICHIGANSTATEUNIV

ERSITy,BUGWOOD.ORG

NANCyROSE

RINK,G.1990

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wood commands a high market price toda orman uses including urniture, veneer, cabinets,paneling, specialt products such as instrumentcases, interior woodwork, and ne woodwork-ing. The librar o Gre Towers, a NationalHistoric Site near Milord, Pennslvania, andormerl the home o Giord Pinchot, the rstchie o the United States Forest Service, is pan-eled entirel with butternut (Fig. 5).

A Deadl Disease Arrives

Sadl, a devastating canker disease has causedrange-wide butternut mortalit in recentdecades and threatens the survival o the spe-cies. Unusual stem can-kers were rst observed onbutternuts in southwest-ern Wisconsin in 1967(Renlund 1971). A pestalert announcing butter-

nut decline was issued in1976 (USDA 1976), and b1979, the ungus respon-sible or butternut cankerdisease, Sirococcus clavi-

gignenti-juglandacearum,was described as a newspecies (Nair et al. 1979).Surves o butternut treesin Wisconsin in the 1990srevealed that 92% werediseased and 27% were

dead (Cummings-Carlson 1993; Cum-mings-Carlson and Guthmiller 1993).B the earl 1990s butternut canker wasreported in Canada (Davis et al. 1992), and

butternut is now considered an endan-gered species in that countr. In 1992, thestate o Minnesota placed a moratoriumon the harvest o health butternut onstate lands, and butternut is considereda species o special concern in all UnitedStates National Forests.

Although the origin o the ungus isuncertain (evidence suggests it ma havecome rom Asia), it is believed to havebeen introduced into North America as a

single isolate (Furnier et al. 1999). Butter-nut trees o all ages and sizes, regardlesso site conditions, can be inected. The

spores o the ungus are spread b rain splashand aerosols to adjacent trees where new inec-tions originate at lea scars, lateral buds, barkwounds, and natural bark cracks. Perennialcankers eventuall develop on twigs, branches,stems, and even the buttress roots (Tisserat andKuntz 1983). Cankers can be seen most easil ithe bark is removed, revealing a sunken, ellip-ticall-shaped region o dark brown to black

stained wood, oten with an ink black centerand a whitish margin (Ostr et al. 1996) (Fig. 6).Cankers reduce the qualit and marketabilito the wood, and the girdling eect o multiplecoalescing cankers eventuall kills a host tree.

Figure 5. The librar at Gre Towers National Historic Site is paneledin butternut.

Figure 6. Health butternut (let), and tree with bark removed showing cankers (right).

PHOTOONLEFTByKEITHWOESTE.PHOTO

ONRIGHTUSDAFOREST

SERVICEFORESTHEALTHPROTECTIONST.PAULARCHIVE,USDA

FOREST

SERVICE,BUGWOOD.ORG

COURTESyOFGREyTOWERSN

ATIONALHISTORICSITE

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While its spread to adjacent trees isunderstood, just how the ungus trav-els long distances to ind new hostsremains a mster. Several beetle spe-

cies have been ound on inected treescarring ungal spores (Katovich andOstr 1998; Halik and Bergdahl 2002),but it is not known which species (ian) carr spores over long distances.The ungus has also been ound on theruits o butternut and black walnut,causing lesions on the husks o bothspecies (Innes 1998), which means thatthe movement o seeds can also spreadthe disease.

Conservation and Restorationo Butternut

There is no cure or butternuts oncethe become inected with butternutcanker. In order to maintain butternutpopulations, conservationists must relon a strateg o encouraging the growtho as man oung, health trees as pos-sible. The methods used include themanagement o regeneration (oten bimproving local habitats or seedling

establishment) and reintroduction (orexample, planting butternuts into suit-able habitats rom which the havebeen lost) (Ostr et al. 1994).

Butternut is a pioneer species, itsseedlings require ull sun to thrive (Rink 1990),and the presence o areas o exposed soil seemsto benet its establishment (Woeste, personalobservation). These actors explain wh oungbutternuts tend to be ound now on road-cuts,steep terrain, ence-rows, old elds, clear-cuts,

washouts, and the banks o switl lowingstreams. The management o most hardwoodorestsboth public and privateavors min-imal disturbance, so there are relativel ewlarge, sunn openings or butternut seedlings tond a oothold. Browsing and antler rubbing bdeer also limit the growth and survival o but-ternut seedlings in the ew sites sunn enoughto support regeneration (Woeste et al. 2009).

Butternut canker, o course, also plas animportant role in reducing the natural regen-eration o butternut (Ostr et al. 1994). A high

percentage o the mature butternuts grow-ing in the eastern orest are cankered, andinected trees have limited energ reservesto put towards lower and ruit production.Because butternuts almost never sel-pollinate(Ross-Davis et al. 2008b), when a high percent-

age o the trees in an area become diseased orare killed, the number o potential mates canbe reduced to the point that adverse geneticand demographic consequences become likel(Geburek and Konrad 2008).

For all the above reasons and more, poor nat-ural regeneration has been a hallmark o thebutternut canker epidemic (Ostr and Woeste2004; Thompson et al. 2006). Until we learnhow to eectivel assist natural regenerationo butternuts, reintroduction will be neededto restore butternut populations to the eastern

Figure 7. Foresters identied this health butternut in a central Indiana orest.

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orest. Reintroduction, whether b aoresta-tion (establishing plantations on old elds) orb supplemental planting in existing habitats,requires a read source o seeds. Seeds romgeneticall diverse and locall adapted sourcesare preerred (Broadhurst et al. 2008). Because

seed supplies rom wild trees are so unreliable,numerous state and ederal agencies as wellas private nurseries have worked over the past20 ears or so to document the location andhealth o butternut trees that could be used asseed sources (Fig. 7). Others have collected andgrown butternut trees to provide seeds that willbe needed or reintroduction.

These collections constitute a germplasmrepositor or butternut, a living bridge to theuture, and a method or preserving the geneticdiversit o the species in the ace o a devastating

population crash. Butternut collectionsmust be conserved as living specimensgrowing in arboreta or other repositoriesbecause butternut seeds do not remain

alive in long-term storage (even con-trolled-environment seed banks) unlikethe seeds o man other species (Bon-ner 2008). Butternut can be propagatedvegetativel b cuttings (Pijut andMoore 2002), through tissue culture(Pijut 1997; Pijut 1999), and b grating.

The ideal seed source or butternutreintroductions would be an orchardo geneticall diverse, locall adapted,and canker-resistant butternut trees.

Starting in the 1980s, a small groupo scientists began identiing, grat-ing, and growing butternuts thatappeared health even though thewere growing in locations with mandead or diseased trees (Ostr et al.2003). It was assumed that these can-didate trees had been exposed to thecanker disease ungus, but becausethe remained healthor at leastsuicientl health to continue togrow and reproduceit was hoped

that some o them would have genesor resistance to butternut canker. Bthe late 1990s, about 200 o these treeshad been identiied b Dr. MichaelOstr o the USDA Forest Service North-

ern Research Station in St. Paul, Minnesota, andother colleagues.

Butternut or Buart?

B growing a large number o butternutstogether in one location, Ostr and others were

able to observe dierences among these treesthat had not been obvious at the time o collec-tion. Dierences in traits such as nut size andbranch habit led him to wonder i some o thecollected butternuts were, in act, buarts (Ostrand Moore 2008). A buart (pronouncedbew-art),also called a buartnut, is the common name orJuglans bixbyi (hbrids between butternut andthe exotic Japanese walnut) (Fig. 8). Buarts werewell known among nut growing enthusiastsin the United States and Canada, but virtuallunknown b dendrologists and orest biologists

Figure 8. The trunk o a ver old buart growing in central Indiana.

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(Ashworth 1969). Buarts had probabl alreadbeen growing unnoticed in ards and orchardsor a generation when the were rst describedb Willard Bixb in 1919 (Bixb 1919).

Japanese walnuts were introduced into theUnited States around 1860 (Crane et al. 1937).In Japan, these walnuts were exploited as a oodsource b earl tribal settlers (Koama 1978),but never became an important commercial nutcrop. B the late 1800s, Japanese walnuts hadbecome popular among nut growers in the east-ern United States because the kernels separateeasil rom the shell, and because some horti-cultural selections o Japanese walnut have anattractive and distinctivel heart-shaped shell

(Crane et al. 1937) (Fig. 9). Trees bearing heart-shaped nuts became known as heartnuts (tech-nicall J. ailantifolia var. cordiformis), and thehbrid combination o btternut plus heartnutresults in the common name buart.

Cultivars o heartnut have been selectedand named (Ashworth 1969; Woeste 2004), butheartnuts never became a market success in theUnited States, perhaps because the nuts, whileexotic in appearance, tend to be bland tasting.Although Japanese walnut never became popu-lar as a nut crop, it gained a permanent oot-

hold in the New World b intermating withbutternut. Over time, as buarts became morecommon and as the gene pools o butternut andJapanese walnut intermixed, it became almostimpossible and certainl impractical or mostpeople to distinguish butternuts rom buarts(Fig. 10). As earl as 1919, Bixb (1919) oundthat [c]ertain Japan walnuts [are] so near likebutternuts as to be readil mistaken or them. . . .[A]s ar as the appearance o the nuts was con-cerned, the butternut could not be well sepa-

rated rom certain Japan walnuts.Buarts are remarkable hbrids. The standout as exceptionall vigorous trees, sometimesexceeding 40 inches (102 centimeters) in diam-eter when mature (butternuts tpicall reach 12to 24 inches [30 to 61 centimeters] in diameter).Buarts oten bear enormous crops o nuts, andtpicall appear to be resistant to butternutcanker (Orchard et al. 1982), although it is notcertain that these trees trul are more resis-tant. It is eas to see wh nut enthusiasts oundbuarts so attractive.

As butternut populations dwindled and dis-appeared because o canker, buarts began toconound butternut conservation. Buarts weremistakenl identied as butternut survivors,

and buarts planted in ards, parks, and cemeter-ies attracted seed collectors who gathered andsold the nuts to nurseries or through local mar-kets, made them available through local con-servation groups, or simpl gave them awa toriends and neighbors. Concerns about butter-nuts status in the orest caught some unawarebecause there were so man large, health but-ternuts (reall buarts) growing in armards allover the countrside. It is likel that landown-ers have planted man more buarts than butter-nuts over the past 20 ears, since so man o the

Figure 9. A distinctivel shaped heartnut (center)surrounded b nuts o other (non-heartnut) orms oJapanese walnut. All the nuts in the photo came rom

Japanese walnuts grown at the National Clonal Germ-plasm Repositor orJlan, in Davis, CA.

Figure 10. Butternut (top row) and hbrid nuts (bottomrow) with the husks removed look nearl identical.

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CHARACTERISTICS BUTTERNUT BUTTERNUT HyBRIDS

HABITAT Forests, occasionall as a gratedtree or wildling

Parks, orest edges, armards, urban areas,planted trees, orchards

1-yR-Twigs

CURRENT-yEAR STEM Olive green changing to red-brownnear terminal, gloss, ew hairsexcept immediatel beneathterminal buds

Bright green to copper brown or tan, otendensel covered with russet or tan hairs,especiall near terminal buds. Pale greennear terminal bud

TERMINAL BUD Beige in color; longer and nar-rower than hbrids, and theouter, fesh scales more tightl

compact.

Pale green to tan or ellowish in color, widerand squatter thanJ. cnra. Outer feshscales more divergent than butternut and

oten deciduous.

LATERAL BUD Vegetative buds are elongated(sometimes stalked) and some-what angular, cream white tobeige in color

Vegetative buds are rounded, and green togreenish brown in color.

LENTICELS Small, round, abundant, evenldistributed, sometimes elongat-ing horizontall across the branch(perpendicular to the stem axis)

Large, oten elongating laterall down thebranch (parallel to the stem axis) on 1-r-wood, patch distribution. On 3 and 4-r-wood, lenticels oten orm a diamond patternas the become stretched both transverseland longitudinall

LEAF SCAR Top edge almost alwas straightor slightl convex; scar usuallcompact

Top edge almost alwas notched; oten withlarge, exaggerated lobes

PITH Dark brown Dark brown, medium brown or evenlight brown

MATuRe TRee

BARK Varies rom light gre and plat todark gre and diamond patternedin mature trees. In older trees,ssures between bark ridges mabe shallow or deep but are consi-stentl dark gre in color.

Silver or light gre, rarel darker. Fissuresbetween bark ridges moderate to shallow indepth and oten tan to pinkish-tan in color.

LEAF SENESCENCE Leaves ellow and brown b earl-mid autumn, dehiscing in earl tomid autumn.

Leaves oten green until late autumn,dehiscing in late autumn or ma reezegreen on the tree.

CATKINS 512 cm in length at peakpollen shed

1326 cm in length at peak pollen shed

NUT CLUSTERS One or two nuts per terminal inmost clusters, sometimes 35,rarel more.

Usuall 3 to 5 per cluster, sometimes asman as 7.

Figure 11. Summary of Characteristics Distinguishing Pure Butternutfrom Hybrid Butternuts.

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remaining butternut trees have lowvigor because o the eects o butter-nut canker and because butternuts,even when health, usuall onl pro-

duce a crop ever two to three ears(Rink 1990).

For butternut, the existence othese hbrids presents something oa dilemma. On the one hand, buartsrepresent the dilution and potentialloss o a distinctive native specieswith deep cultural connections and acomplex quilt o ecological roles thatevolved over man hundreds o thou-sands o ears. On the other hand,

hbridization is a common theme inplant evolution (Wissemann 2007),and or butternut, hbridizationcould represent a wa orward, espe-ciall i it is determined that all but-ternuts are completel susceptible to butternutcanker (something that is ar rom certain atthis point). What role hbrids will pla in but-ternut recover remains to be seen.

Detailing the Dierences

Whatever the possible uses o buarts, b 2003

it became clear to researchers that the neededreliable mechanisms to distinguish buarts rombutternuts (McIlwrick et al. 2000; Ostr et al.2003; Michler et al. 2005). The rst task wasto describe the two parental species. Publisheddescriptions o the vegetative and reproductivetissues o butternut, Japanese walnut, and thehbrids are oten brie, and based on an unknownnumber o samples o unidentied provenance.B surveing published descriptions o butter-nut, especiall those made beore the introduc-

tion o Japanese walnut to the United States orbeore hbrids had an opportunit to becomewidespread, a clearer picture o the morphol-og o butternut and Japanese walnut emerged(Ross-Davis et al. 2008a). To veri our ind-ings, we examined old butternut specimens atthe Herbarium o the Missouri Botanical Gar-den. These long-preserved samples providedadditional certaint that what we saw in thewild toda matched what was collected over100 ears ago. We also obtained authenticatedsamples o Japanese walnut rom the National

Clonal Germplasm Repositor in Davis, Cali-ornia, or comparison.

Armed with the best possible descriptions obutternut and Japanese walnut, we had to con-clude that trees with intermediate traits werebuart hbrids. Ater examining a large numbero samples we developed a list o characters that

can be used in combination to separate butter-nut and hbrids (Woeste et al. 2009) (Fig. 11).Ater a ew ears o observing these traits in theeld we have trained our ees and now nd thatmost hbrids are airl eas to spot, though ormore complicated cases a careul examinationis needed to make a determination. (Fig. 12)

At the same time, we began development oa series o DNA-based tools or identiing but-ternuts and hbrids (Ross-Davis et al. 2008a).The DNA markers are being used in both the

United States and Canada to identi true but-ternut seed sources. To understand the geneticdiversit o butternut, we developed DNA-based markers called microsatellites, and usedthese to evaluate samples o butternuts romive locations spanning the upper south andmidwestern United States. To our relie, welearned that the genetic structure and neutralgenetic diversit (diversit at the DNA levelthat is not associated with genes) o the currentgeneration o large, standing butternuts wasquite similar to that o black walnut, a much

Figure 12. Twigs o butternut (top and bottom), Japanese walnut (upper middle,)and buart (lower middle). The shape o the lenticels is characteristic o each tpe.

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more common related species (Ross-Davis et al.2008b). This observation held out hope that itwas not too late to begin to collect and preservethe genetic diversit o butternut.

Armed with new DNA-based markers, andsupport rom The Nature Conservanc and theUSDA Forest Service State and Private For-estr, a small group o scientists and collabora-tors spent 2008 collecting butternut seeds aspart o a long-term gene conservation program.A permanent home or the seedlings that willgrow rom these seeds is envisioned in westernIowa, sucientl distant rom sources o but-ternut canker it is hoped, to ensure the collec-tion will be sae. These trees represent one oseveral collections that will reconstitute theuture or butternut.

A nal note o good news is that an evalu-ation o candidate canker-resistant butternutsusing our DNA-based methods conrms that

man o the trees are trul butternuts and nothbrids (Woeste, unpublished data). Recentl,pathologists proposed protocols or inoculatingand testing candidate trees to determine i theseare trul resistant to butternut canker (Ostrand Moore 2008) (Fig. 13). I uture pathologstudies demonstrate that some candidate treescontain useul levels o resistance to butternutcanker, an aggressive program o breeding willbe undertaken to transer the resistance genesinto butternuts rom all across the speciesrange. The goal will be to produce seed orchardso geneticall diverse, regionall adapted, disease-resistant butternuts or reintroduction to areaso the eastern orest where butternut has disap-peared. Learning how to reintroduce and sus-tain viable populations o trees into habitatsrom which the have been lost remains animportant and ongoing challenge (Broadhurstet al. 2008; Geburek and Konrad 2008).

Figure 13. young butternut trees are screened or canker resistance at the Hardwood Tree Improvement and Regenera-tion Center in West Laaette, Indiana.

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Reerences

Aradha, M., D. Potter, F. Gao, and C. Simon. 2007.Molecular phlogen o Juglans (Juglandaceae):a biogeographic perspective. Tree Genetics and

Genomes 3: 363378.Ashworth, F.L. 1969. Butternuts, Siebold (Japanese)

Walnuts, and Their Hbrids. pp. 224231, In:Handbook of North American Nut Trees. Janes,R.A. (ed.),. Northern Nut Growers Association,Knoxville, TN.

Bixb, W.G. 1919. The butternut and the Japan walnut.American Nut Journal 10 (6): 7683.

Bonner, F. T. 2008. Juglans L. pp. 601606, In: The WoodyPlant Seed Manual. Bonner F.T., Karralt,R.P., and Nisle, R.G. USDA Forest ServiceAgricultural Handbook 727.

Brinkman, K.A. 1974. Juglans L. Walnut. pp. 454459,In : Seeds of Woody Plants in the UnitedStates. C.S. Schopmeer (Tech. Coord.), USDAForest Service Agriculture Handbook 450,Washington, DC.

Broadhurst , L.M., A. Lowe, D.J . Coates, S.A.Cunningham, M. McDonald, P.A. Vesk, andC. yates. 2008. Seed suppl or broad-scalerestoration: maximizing evolutionar potential.Evolutionary Applications 1: 587597.

Crane H.L, C.A. Reed, and M.N. Wood. 1937. NutBreeding. pp. 827889, In: USDA Yearbook of

Agriculture: 75th Congress, 1st Session. HouseDocument No. 28.

Cummings-Carlson, J. 1993. Butternut: Are there anhealth trees let? Woodland Management,Spring: 1112.

Cummings-Carlson, J. and M. Guthmiller. 1993. Incidenceand severit o butternut canker in Wisconsinin 1976 and 1992. Phytopathology83: 1352.

Davis, C.N., D.T. Mren, and E.J. Czerwinski. 1992. Firstreport o butternut canker in Ontario. PlantDisease 76: 972.

Dirr, M.A. 1998. Manual of Woody Landscape Plants: TheirIdentification, Ornamental Characteristics,Culture, Propagation and Uses. 5th ed., StipesPublishing, Champaign.

Fjellstrom, R.G. and D.E. Partt. 1994. Walnut (Juglansspp.) genetic diversit determined b restrictionragment length polmorphisms. Genome 37:690700.

Flora o North America Editorial Committee. 1993+.Flora of North America North of Mexico, 7+vols. New york and Oxord.

Furnier, G.R., A.M. Stolz, R.M. Mustaphi, and M.E. Ostr.1999. Genetic evidence that butternut cankerwas recentl introduced into North America.Canadian Journal of Botany77 (6): 783785.

Geburek, T. and J. Konrad. 2008. Wh the conservationo orest genetic resources has not worked.Conservation Biology22 (2): 267274.

Goodell, E. 1984. Walnuts or the northeast.Arnoldia 44(1): 319.

Halik, S. and D.R. Bergdahl. 2002. Potential beetle vectorso Sirococcus clavigignenti-juglandacearum onbutternut. Plant Disease 86: 521527.

Innes, L. 1998. Sirococcus clavigignenti-juglandacearumon butternut and black walnut ruit. pp. 129132, In: Foliage, Shoot, and Stem Diseases ofTrees; Proceedings of the International Unionof Forest Research Organizations. LaFlamme,G.; Berube, J.A.; Hamelin, R.C. (eds.) WorkingPart 7.02.02; 1997 Ma 2531; QuebecCit, Canada.

Johnson, L. 1884. Manual of the Medical Botany of NorthAmerica. W. Wood and Co., New york.

Katovich, S.A. and M.E. Ostr. 1998. Insects associatedwith butternut and butternut canker inMinnesota and Wisconsin. The Great LakesEntomologist 31: 97108.

Koama, S. 1978. Jomon subsistence and population.Senri Ethnological Studies 2: 1246.

Krochmal, A. and C. Krochmal. 1982. Uncultivated nutso the United States. USDA Forest ServiceAgriculture Inormation Bulletin 450.

Manning, W.E. 1978. The classiication within theJuglandaceae.Annals of the Missouri BotanicalGarden 65: 10581087.

McDaniel, J.C. 1981. Other walnuts including butternut,heartnut, and hbrids. pp. 98110, In: Nut TreeCulture in North America. R.A. Janes (ed.),Northern Nut Growers Association, Hamden.

McIlwrick, K., S. Wetzel, T. Beardmore, and K. Forbes.2000. Ex situ conservation o Americanchestnut (Castanea dentata [Marsh.]) andbutternut (Juglans cinerea L.), a review. ForestryChronicle 76: 765774.

Michler, C. H., K.E. Woeste, P.M. Pijut, D.F. Jacobs, R.Meilan, and M. Ostr. 2005. Improving diseaseresistance o butternut (Juglans cinerea) athreatened ne hardwood: a case or single treeselection through genetic improvement. Tree

Physiology26: 113120.Milikan, D.F. and S.J. Stean. 1989. Current status o the

butternut, Juglans cinerea L. Annual Reportof the Northern Nut Growers Association80: 5254.

Milikan, D.F., S.J. Stean, and K.S. Rigert. 1990. Selectionand preservation o butternut, Juglans cinereaL.Annual Report of the Northern Nut Growers

Association 81: 2225.

Nair, V.M.G., C.J. Kostichka, and J.E. Kuntz. 1979.Sirococcus clavigignenti-juglandacearum:an undescribed species causing canker onbutternut. Mycologia 71: 641646.

Butternut 11

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Orchard, L.P., J.E. Kuntz, and K.J. Kessler, Jr. 1982.Reaction o Juglans species to butternut cankerand implications or disease resistance. pp.2731, In: Proceedings of Conference on BlackWalnut for the Future. General Technical Report

NC-74. USDA Forest Service, North CentralForest Experiment Station, St. Paul, MN.

Ostr, M.E., M.E. Mielke, and D.D. Skilling. 1994.ButternutStrategies or managing a threatenedtree. General Technical Report NC-165. USDAForest Service, North Central Forest ExperimentStation, St. Paul, MN

Ostr, M.E, M.E. Mielke, and R.L. Anderson. 1996.How to identi butternut canker and managebutternut trees. HT-70. USDA Forest Service,Northeastern Area State and Private Forestr.

Ostr, M.E. and P.M. Pijut. 2000. Butternut: An underused

resource in North America. HortTechnology10(2): 302306.

Ostr, M.E., B. Ellingson, D. Seekins, and W. Ruckheim.2003. The need or silvicultural practices andcollection o butternut germplasm or speciesconservation. pp. 551555, In: Proceedings of13th Central Hardwood Forest Conference.General Technical Report NC-234. USDAForest Service, North Central Research Station,St. Paul, MN

Ostr, M. E. and K. Woeste. 2004. Spread o butternutcanker in North America, host range, evidenceo resistance within butternut populations and

conservation genetics. pp. 114120, In: BlackWalnut in a New Century, Proceedings of 6thWalnut Council Research Symposium. Michler,C.H. et al., eds.; 2004 Jul 2528, Laaette,IN. General Technical Report NC-243. USDAForest Service, North Central Forest ExperimentStation, St. Paul, MN.

Ostr, M.E. and M. Moore. 2008. Response o butternutselections to inoculation with Sirococcusclavigignenti-juglandacearum. Plant Disease92: 13361338.

Peattie, D.C. 1950.A Natural History of Trees of Easternand Central North America. Houghton Mifin,

Boston.Pijut, P.M. 1997. Micropropagation o Juglans cinerea L.

(Butternut). pp. 345357, In: Biotechnology inAgriculture and Forestry, Vol.39, High-Techand Micropropagation, Section III.4:, Bajaj,y.P.S. (ed.). Springer-Verlag, Berlin, Heidelberg,New york.

Pijut, P.M. 1999. Somatic embrogenesis rom immatureruit o Juglans cinerea. pp. 415429, In:Somatic Embryogenesis in Woody Plants, Vol.4,Section B: Jain. S.M., Gupta, P.K., and Newton,R.J. (eds.)., Kluwer Academic Publishers, TheNetherlands.

Pijut, P.M. and M.J. Moore. 2002. Earl season sotwoodcuttings eective or vegetative propagation oJuglans cinerea. HortScience 37 (4): 697700.

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In:Annual Report of the Wisconsin Departmentof Natural Resources, Madison, WI.

Rink, G. 1990. Juglans cinerea L., Butternut. pp. 386390,In: Silvics of North America, Vol 2. Hardwoods.R.M. Burns and B.H. Honkala (Tech. Coords.).USDA Forest Service Agriculture Handbook654, Washington, DC.

Ross-Davis, A., Z. Huang, J.R. McKenna, M.E. Ostr, andK. Woeste. 2008a. Morphological and molecularmethods to identi butternut (Juglans cinerea)and butternut hbrids: relevance to butternutconservation. Tree Physiology28: 11271133.

Ross-Davis, A., M.E. Ostr, and K. Woeste. 2008b.Genetic diversit o butternut (Juglans cinerea)and implications or conservation. CanadianJournal of Forest Research 38 (4): 899907.

Schultz, J. 2003. Conservation assessment or butternut orwhite walnut (Juglans cinerea L.). USDA ForestService, Eastern Region. On-line at www.s.ed.us/r9/wildlie/tes/ca-overview/docs/plant_juglans_cinera-Butternut2003.pd

Thompson, L.M., F.T. van Manen, S.E. Schlarbaum, andM. DePo. 2006. A spatial modeling approachto identi potential butternut restoration sitesin Mammoth Cave National Park. RestorationEcology14: 289296.

Tisserat, N. and J.E. Kuntz. 1983. Dispersal gradientso conidia o the butternut canker ungus in aorest during rain. Canadian Journal of ForestResearch 13 (6): 11391144.

USDA. 1976. Butternut decline. Pest Alert. USDA ForestService, Misc. Publication Newtown Square,PA, Northern Area State and Private Forestr.

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Wissemann, V. 2007. Plant evolution b means o

hbridization. Systematics and Biodiversity5: 243253.

Woeste, K. 2004. An On-line Database o Juglans CultivarNames and Origins. HortScience 39: 1771.

Woeste, K., L. Farlee, M. Ostr, J. McKenna, and S. Weeks.2009. A orest managers guide to butternut.Northern Journal of Applied Forestry.

Keith Woeste and Paula M. Pijut conduct research atthe USDA Forest Service Northern Research Station Hardwood Tree Improvement and Regeneration Centerin West Laaette, Indiana.

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Walk into the Arnold Arboretum andoull see a beautiul and histori-call important collection o trees

and shrubs. With a closer look, other organ-isms become visible, including ungi. Theworld o ungi is vast, and man memberso this diverse kingdom are ound through-out the Arboretum. In an inormal surverom spring through all o 2008, Arboretumsta reported over 100 ungal sightings, andpositive identiications were made or 40species. A dozen species noted in the surveare proled starting on page 15.

Plants + Fungi

The association between plants and ungi issometimes benecial, sometimes harmul,and sometimes a bit o both. Fungi can beindicators o a trees declining health, butin other casessuch as mcorrhizae which

aid roots with nutrient uptakethe arephsiologicall benecial to plants. Identi-ing ungi and understanding their phsi-olog is an important aspect o interpretingthe health o the Arboretums collections.

The Arnold Arboretum hosts anunknown number o ungi, man o whichhave speciic relationships with certainplants. When a ungus is ound growingon an accessioned tree, horticultural staattempt to make an accurate identication,and oten those known relationships aid inthe identication process. For example, ashin bracket ungus growing on easternhemlock (Tsuga canadensis) is probabl thehemlock varnish shel (Ganoderma tsugae),and an oak tree with a massive cluster osulphur-ellow mushrooms growing romits roots is likel to be chicken o the woods(Laetiporus sulphureus).

These ungi ma live in their hosts orseveral ears. As the eed, these ungicause wood deca and oten weaken the

A Closer Look at Fungi in the Arnold Arboretum

Kathryn Richardson

Fungi IDPRECISELy identiing ungi can be challenging

even or experts. Man morphological eatures

rom growth habit to the size and color o spores

provide clues or identiication. Oten minute

details are needed to conrm species identit.

Correct identication is critical when consider-ing ungi as ood, since the ungi kingdom contains

species that are deliciousl edible and others that

are deadl poisonous. Though oten stated, its

worth repeating: Never consume an mushroom

without being absolutel sure o its identit.

The distinctive lamellae (gills) o this mushroom mark itas a member o the phlum Basidiomcota, but much moreinormation is needed to determine its exact species.

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structural integrit o the tree. Damage romungi also weakens the trees deenses andma enable entr or other pests and diseaseswhich cause urther injur. Arboretum trees

fagged with potentiall atal ungi are careullobserved and notes are kept within the Arbore-tums collections database. I the tree begins todecline, this inormation is useul in making adecision on its treatment or removal.

The Fungal Lie

Fungi are neither plant nor animal and are placedin their own kingdom, though historicall thiswas not alwas the case. Taxonomists initiallplaced ungi in the plant kingdom (Plantae)

because, plants and ungi are both sessile (notree-moving) and have cell walls. However, ungilack chlorophll (and thus cannot make their ownood via photosnthesis) and have walls madeo chitin, not cellulose as seen in plants. Fungiare closel related to animals and bacteria andwere once placed in the animal kingdom (Anima-lae), but ungi are not motile. Fungi proved to beunique lie orms deserving their own kingdom.

Fungi cannot produce their own ood andthus must acquire the nutrients the need romtheir hosts or substrates. Based upon their nutri-

tional needs, ungi all into three categories:saprobes, parasites, and mutualists. Saprobicungi eed on dead organic materials and serveas the scavengers o the kingdom b recclingcarbon, nitrogen, and other essential elementsback into the soil. Parasitic ungi eed on livingorganisms and oten harm them in some wa.Parasitize sounds threatening, but the realitis that ungal parasites do not tpicall destrotheir host quickl and ma be present or sometime beore the host shows decline. Mutual-

istic ungi have a benecial relationship withother living organisms. Examples o mutualistsinclude lichens (ungi plus algae or canobacte-ria) and mchorrhizae (ungi and plant roots).Around 90% o all living trees have a mcor-rhizal relationship with ungi.

The presence o ungal ruiting bodies ontrees indicates that the ungus has reached thespore production stage o its lie ccle. Whenreleased spores land on a substrate and germi-nate, threadlike hphae grow and combine toorm mcelia, the vegetative growth o ungi.

Mcelia grow underground (sometimes spread-

ing or miles), or within wood or other hosts.Mcelia grow even when no ruiting bodies arepresent, so the extent o damage caused b aungus in the tree beore the emergence o the

ruiting bod is sometimes unclear.

Fungi to Know

The largest groups o ungi are ound in the ph-lum Basiodiomcota, oten inclusivel calledthe basidiomcetes. Man amiliar ungi suchas cap-and-stipe (stalk) mushrooms (includingthe cultivated white button mushroom [Aga-

ricus bisporus] ound in grocer stores), brack-ets, and puballs are placed in this group. It issae to sa that i ou are looking at a ungus

that has either rib-like gills (lamella) or tinpores on the underside o the cap, its a basidi-omcete. The microscopic rust and smut ungiare also basidiomcetes.

Basidiomcota produce basidiospores whichhave a single haploid nucleus. When thesespores germinate the produce long, branch-ing hphae with a single nucleus in each com-partment (area between cell walls). When twocompatible hphal strands come into contactwith each other the unite to orm a hphalstrand that now houses two nuclei in each com-

partment. A basidiomcete will spend most oits lie in the vegetative mcelial stage untilenvironmental cues, such as rain or tempera-ture change, cause the growth o ruiting bod-ies (basidiocarps). Man basidiomcetes aredecomposers, but others have a mcorrhizalpartnership with orest trees.

Another ungal phlum, Ascomcota,includes the sac ungi or spore shooters. Unlikebasidiomcetes that have structures (basidi-ophores) that drop spores rom their ruiting

bodies, ascomcetes have spores in sacs locatedwithin a structure called an ascocarp or asco-mata. The spores are shot out o their sacsand dispersed into the air. Sac ungi are alsodecomposers and recclers o organic matter.Man ascomcetes are parasitic including thosethat cause Dutch elm disease and chestnutblight. Ascomcetes include easts, which areused to make beer and wine, as well as mcelialungi such as morels and black knot. Anotherinteresting example o an ascomcete is theungus that causes ergot, a damaging disease o

grain crops. Ergot ungus contains a compound

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Fungi 15

that is a precursor to the hallucinogen LSD.Though not proven, it has been suggested thatergot poisoning was a potential cause o thehsteria that led to the Salem witchcrat trials

in the late 1600s.

Although no longer classiied in the ungikingdom, Mxomcetes (slime molds) are alsomentioned here since the resemble ungi, arecommon at the Arboretum, and elicit man

questions rom visitors (see page 21).

A Sampler of Arboretum Fungi

Here are a dozen interesting fungiplus one slime moldthat were found

in last years informal survey of fungi at the Arnold Arboretum

Pheasants-back Polporeor Drads Saddle (Polpor

qamo)In the spring o 2008, a ver large

pheasants-back polpore appeared

on a venerable cucumbertree

magnolia (Magnolia acuminata,

accession 15154-E) near the main

entrance o the Arnold Arbore-

tum. This magnolia has survived

or over 100 ears, but time has

taken its toll and the doors are

now open or various organisms,including ungi, to invade.

Growing out o an old limb-removal wound on the magnolias trunk was

an impressive bracket with a uniquel patterned cap. This species, the

pheasants-back polpore, can grow to 24 inches (61 centimeters) in diameter.

It appears growing on stumps and dead hardwood trees in spring in the north-

eastern United States. It is easil recognized b its an-shaped, tan to cream

ellowish cap with an arra o brown scales that look like pheasant eathers

thus the species common name. (Another common name, drads saddle,

reers to its potential use b the tree-dwelling nmphs known as drads in

Greek mtholog.) The white underside o the cap is dotted with thousandso small pores (polyporus means man pores).

It was sad to see this particular polpore because it indicates that this

magnolias lie is coming to an end. The Arboretums horticultural sta

had noted the trees decline beore the emergence o this polpore, but its

presence told us more about the health o this tree. The pheasants-back

polpore is tpicall saprobic on dead trees but it can also parasitize the

heartwood o living trees such as this magnolia. This polpore ungus had

been living in this tree or an unknown period o time beore it produced

this ruiting bod; the extent o internal rot is uncertain but the tree will

continue to be monitored closel.

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16 Arnoldia 66/4

Witchs Butter (Trmlla mntrca)

Witchs butter is a member o the phlum

Basidiomcota, but does not have the tradi-

tional cap and stem as do some other ungi inthis group. This ungus is ellow to orange in

color and appears as wav, gelatinous olds.

It can dr out to the point o appearing dead,

but will rehdrate readil with rainall or

other applied water. Another interesting act

about witchs butter is that it eeds on other

ungi, not on wood. It is oten seen growing

on downed logs or dead branches, where it

parasitizes wood-decaing ungi. Witchs butter is widel distributed in temper-

ate regions in North America, Europe, Asia, and Australia.The name witchs butter comes rom several European legends. One states

that i the ungus was ound growing near a homes entrance or ront gate, then

the homeowner had been hexed b a witch. The spell could be broken b plung-

ing a pin into the ungus, causing the witch to eel the pinpricks, which in turn

would cause her to return to remove the spell and the ungus. A legend o Swed-

ish origin blames this ungus on a witchs cat. The cat, sent out to steal ood rom

the neighbors, would gorge itsel and then vomit witchs butter on the gardens,

ences, gates, and homes o unsuspecting people. The name witchs butter is

sometimes applied to an o a number o jell-like ungi.

The Stink Squid (Pdocol fform)

The stink squid is a basidiomcete belonging to

the Phallaceae, a amil o ungi commonl known

as stinkhorns. The stink squid certainl lives up

to its name both in scent and appearancein late

August 2008 this stinkhorn created quite a horrible

smell in the Arnold Arboretum when it appeared in

a ew beds in the Leventritt Shrub and Vine Garden

as well as in densel planted areas on Peters Hill.

Common to eastern North America, this specieso stinkhorn has a antastic appearance. Beginning

its reproductive lie as an egglike structure with

white rhizomorphs attached to the base, its ruiting

bod quickl emerges, displaing three to ve tapering arms. The arms ma be

ree-standing or used together at the tips, and are ellow towards the base and

reddish orange towards the apex. It stands 1 to 3 inches (3 to 7 centimeters) in

height with dark green spores lining the inner sides o its arms. (A broken-o

ruiting structure is seen here.)

Theres no question about how this ungus received its common name: it looks

like a squid and has the odor o rotting fesh. Stinkhorns, including stink squid,

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Fungi 17

disperse their spores b attracting fies and other insects which land on the un-

gus and eed on the stink slime. In the process, the insects collect spores on

their bodies as well as ingesting them, then spread the spores to new locations.

Common Oster Mushroom (Plrot otrat)

The common oster mushrooma amiliar edible mush-

room that can be ound in grocer storesis common in

the Arboretum and appeared in large numbers last spring.

Oster mushroom species are tpicall ound in the all,

winter, and earl spring, though the are also sometimes

seen in the summer under the right conditions. The

grow on dead hardwoods and, less oten, on coniers, and

also on some living trees. Oster mushrooms grow in

dense clusters, have light brown to o-white caps, anddispla prominent, elongated white gills.

An interesting act about species in this mushroom

genus is that the are carnivorous; the trap, kill, and

eat living organisms such as nematodes and bacteria in

addition to the more tpical ungus unction o decom-

posing wood.

Chicken o the Woods (Latporlphr)

Chicken o the woods belongs to the genus

Laetiporus, which airl recentl has been

separated into several species based on

DNA analsis. When I rst began identi-

ing chicken o the woods in the Arboretum

I assumed it was Laetiporus sulphureus,

but most turned out to be the ver sim-

ilar-looking species Laetiporus cincinna-

tus. Both species have the common name

chicken o the woods and are popular

edibles or mushroom hunters. The arereadil identied because o their bright ellow to orange color and appearance

as masses or rosettes o wav, blunt-rimmed plates. The are widel distributed

east o the Rock Mountains and oten grow as parasites or saprobes on oaks

(Quercus spp.). The main dierence between the two species is the location o

their ruiting bodies; Laetiporus sulphureus usuall grows on tree stumps while

L. cincinnatus grows rom the roots o the inected host, giving the appearance

that it is growing terrestriall.

The common name is appropriate or several reasons. The fesh o the caps is

ellowish in color, almost like raw chicken. Also, the taste and texture o this

ungus, when cooked, reportedl are similar to cooked chicken.

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18 Arnoldia 66/4

Turke Tail Fungus (Tramt vrcolor)

The turke tail ungus is one o the most commonl

seen bracket ungi, occurring on dead trees in temper-

ate zone orests all over the world. Turke tail ungusis saprobic on dead hardwoods and can sometimes

completel cover trunks and branches. A decomposer

o wood, this ungus will sometimes work awa or

hundreds o ears on a single host.

Turke tail ungus is a polpore, having pores

instead o gills, and has a hard exterior instead o the fesh ones seen in tradi-

tional mushrooms. It is aptl named, displaing concentric colored bands that

resemble a anned turkes tail. The colors o turke tail ungus can var, but

the bands commonl appear in shades o white, brown, and tan, sometimes with

more colorul bands in orange, cinnamon, or bluish tones. A close look revealsdense, down hairs on the brackets upper surace.

Shagg Mane Mushroom (Coprn comat)

The shagg manea tpe o ink cap mushroomis readil

observed rom mid-spring to late summer. Found on lawns,

in mulched beds, and in orests, the shagg mane perorms as

one o natures recclers, eeding on soil, orest litter, deca-

ing wood, and even dung. It slowl decomposes the organic

matter on which it eeds.

One characteristic that makes this mushroom interesting

is its method o spore dispersal. When the spores begin to

mature, the shagg oval cap begins to curl, becoming bell-

shaped, as the gills deliquesce (lique). This gives the spores

maximum exposure to the wind, which then transports the

spores to new locations. The gills will continue to lique until the are virtuall

gone, leaving a fat, almost transparent cap. True to the name, the liqueed gills

o this and other ink caps can be used as a semi-permanent ink.

Bark Mcena (Mcna spp.)There are man tin, oten-overlooked mushrooms

growing in the Arboretum including several in the

genus Mycena. This genus contains hundreds o species

distributed worldwide. Most Mcena species are ver

small and have bell-shaped caps on slender stipes.

Walking along Meadow Road I came across an old

painted maple (Acer mono) covered with these tin mush-

rooms. Gra-brown in color with caps no larger than a

ew millimeters in diameter the covered the bark o this

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USDA

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maple along with moss and lichens. At rst it seemed sad to see such a antastic

old tree covered with mushrooms, but these ungi do not harm the tree. Bark

Mycena live on the outer laer o a tree, eeding on the dead bark. The never move

to the living laers o the tree and thus do no harm.

Birds-Nest Fungi (species in several generaincluding Crcblm and Cath)

Birds-nest ungi are a group o unusual ungi in

the order Nidulariales (nidula means small nest).

The are ver common in the Arboretum and can

be ound growing in almost ever mulched bed as

well as on debris in natural woodland areas. These

harmless ungi are saprobic on substrates such as

dead wood (including woodchips), leaves, and dung.The oten grow in large expanses.

The common name describes these ungi per-

ectl. The mature peridia (ruiting bodies) resem-

ble tin nests. These nests contain tin egglike peridioles which contain spores.

Several species o birds-nest ungi grow at the Arboretum and can be dierenti-

ated b the color, size, shape, and texture o their peridia as well as b the color

o their peridioles which can var rom white to black with several shades o

gra and brown in between.

Birds-nest ungi exhibit an interesting spore dispersal method. When it rains,

water droplets splash the eggs (peridioles) out o the nest and into the air.When this happens, a cord which attaches the egg to the nest breaks ree and

elongates. When the egg lands on nearb substrates the cord sticks and secures

the egg to its new site.

Hen o the Woods (grfola frondoa)

Hen o the woods is a popular edible mushroom

with sweet-tasting fesh. The clustered caps o this

ungus resemble the rufed eathers o a hen, and

a ull-grown specimen can reach a oot or more

in diameter and weigh as much as 40 pounds (18kilograms). Hen o the woods is commonl ound

growing on oak (Quercus spp.) trees rom either

the trunk or roots.

This mushroom is a parasite and will cause

damage over time. It causes white rot which can

compromises the structural integrit o the roots.

A weakened root sstem can prove disasterous or

a tree in wind storms, since lack o solid anchor-

age ma allow the tree to topple over.

Fungi 19

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Black Knot Fungus(Apoporna morboa)

Black knot ungus is visible on several cherr

trees b the Arboretums Forest Hills gate.Black knot can inect a number o cherr and

plum species (Prunus spp.). This ascomcete

is a harmul ungus that damages both the

health and appearance o its host. The visible

part o this ungus, a black gall, is the result

o the ungus disrupting the normal growth

o the twig. Galls orm at the site o inec-

tion. Black knot galls look something like burned marshmallows on a stick

and ma eventuall grow to a oot in length i let unchecked.

Inside the galls are perithecia which produce ascospores, which, ater over-wintering in the gall, are ejected in the spring when warmer temperatures and

adequate moisture arrive. The ascospores are then carried b wind and water

to new host sites. Inection occurs on new plant growth and wounded tissues.

These ascospores are able to penetrate through the green tissue o new growth

and quickl begin to grow. New galls are brown, and can easil go unnoticed

until the ollowing ear when the continue to grow and turn black. The galls

continue to grow ever ear and the inection continues to spread urther

down the branch. Older galls oten harbor borers which can cause even more

problems or inected trees.

All trees at the Arnold Arboretum with black knot galls present are moni-

tored. When a gall is ound the inected branch is removed while the ungus is

still dormant. This slows urther spread on the host tree and also reduces the

spread o inection to other trees.

Hemlock Varnish Shel(ganodrma ta)

The Arboretums Hemlock Hill oers

visitors a chance to see the interaction

between a ungus and a specic tpe o

tree. The hemlock varnish shel (Gano-derma tsugae) has a preerence or coni-

ers and specicall or hemlocks (Tsuga

spp.). It is ound on living and allen trees

on Hemlock Hill and was also reported

growing in a mulch bed along Meadow

Road. I seen growing on a living hem-

lock it is sae to sa that the tree is not

in perect health.

20 Arnoldia 66/4

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The hemlock varnish shel is a beautiul polpore. Its hard, shin cap is dark

red to reddish brown, sometimes with prominent concentric zones. young

specimens ma show white and ellow segments also. This annual mushroom

grows individuall or, less commonl, in limited clusters. This species is closel

related to the more common taxa Ganoderma lucidum, (sometimes known as

reishi or lingzhi); extracts o both have been used in herbal medicine.

Dog Vomit Slime Mold(Flo ptca)

I have had Arboretum visitors ask me about

the lump ellow (or tan) stu in the mulch

bed that looks like vomit. Well, thats the

descriptivel named dog vomit slime mold,

commonl seen in planting beds mulchedwith wood chips. Fuligo septica is a tpe

o Mxomcetes, so not a true ungus. It is

a plasmodial slime mold; this means that

the vomit is actuall a huge single cell

containing millions o nuclei.

Dog vomit slime mold is motile, but

moves quite slowl. It is not harmul to

animals or plants and usuall vanishes in a

short period o time. This species and similar slime molds eed on bacteria, un-

gal spores, and smaller protozoa ound on wood chips. Slime molds eed muchlike an amoeba eeds; the ingest their ood and then digest it (unlike ungi,

which digest and then ingest). I conditions are avorable, these slime molds

will produce reproductive structures (sporangia) that produce spores. When

conditions are unavorable (loss o ood, dr conditions), the plasmodium will

orm hard, dormant, protective structures called sclerotia. Inside the sclerotia

the plasmodium will divide into cells containing up to our nuclei. When

conditions become avorable each cell will orm a new plasmodium.

Dog vomit slime mold is primaril an aesthetic problem in mulched garden

beds. It can be phsicall removed, but more is likel to return. So, beore

panicking and taking our dog to the veterinarian, take a closer look andconsider that that stu is likel just Fuligo septica working awa at cleaning

the mulch.

Acknowledgments

Thanks to Susan Hard Brown, Nima Samimi, Eric youngerman, Bob Ervin, Marc Devokaitis,Nanc Sableski, and all sta or their help in surveing and photographing ungi at theArboretum, and to Don Pster or reviewing this article.

Kathrn Richardson is a Curatorial Assistant at the Arnold Arboretum.

Fungi 21

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New England was heavil orested in1600, and American chestnut (Cas-tanea dentata) was commonl ound

in Connecticut and Massachusetts woodlands(Cogbill et al. 2002). At that time, Americanchestnut was abundant throughout its nativerange rom southern Maine to northern Georgia,all along the Appalachian Mountains (Saucier

1973). In the ollowing centuries, European set-tlers cleared land or arming and cut trees oruel, and the orest cover was greatl reduced b1850. This was ollowed b the introduction ocoal as a uel, which was brought easil to NewEngland b the railroads. Once wood was nolonger being harvested or uel, and more eldswere let allow as people abandoned arms andmoved west or into the cities, the trees startedto take back their habitats.

When hardwood orests were harvested andlet to resprout, the chestnuts grew aster than

the oaks and maples with which the shared theland, and the number o chestnut trees greatlincreased. Man woodlots became nearl purestands o chestnut. A bulletin issued b the Con-necticut Experiment Station in 1906 stated thatregenerating hardwood orests covered mosto the wooded area o Connecticut and themost important tree o this tpe is the chestnutwhich constitutes ull one-hal o the timber(Hawes 1906). Forest surves done at the turno the last centur show that there were about

130 million mature American chestnut trees inConnecticut alone.These stands o chestnut trees were valued

because chestnut is a strong wood that resistsrotting. Chestnut was used extensivel or ram-ing and woodwork, and was also essentiall theonl wood used or telephone poles and most othe railroad ties laid as rail lines pushed west-ward (Pierson 1913).

The Blight Arrives

The ungal pathogen causing chestnut blightdisease (now called Cryphonectria parasitica)was introduced into the United States in thelate 1800s on Japanese chestnut trees. The dis-ease was spread up and down the east coast bmail-order sales o inected trees (Anagnosta-kis 2001, http://www.ct.gov/caes/cwp/view.

asp?a=2815&q=376754). In 1908 chestnutblight disease started killing American chest-nut trees in Connecticut (Clinton 1912), and

American Chestnuts in the 21st Century

Sandra L. Anagnostakis

Native range o American chestnut (Catana dntata) inEastern North America.

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American Chestnut 23

inections were reported in Cape Cod, Welles-le, and Pittseld, Massachusetts (Metcal andCollins 1909).

Chestnut blight disease has reduced Ameri-can chestnuts to understor shrubs, which die

back, sprout rom the base, die back, and sproutagain. This ungus is now present throughoutthe original range o C. dentata, and has spreadto man o the Midwestern locations wherechestnuts were planted.

Chestnut Breeding

Chestnut trees are monoecious and bear sepa-rate male and emale fowers on the same tree.

As with man ruit trees, the must be cross-pollinated or ull ormed nuts to develop.Without cross-pollination, burs with small,lat nuts comprised o all-emale tissue areall that orm. Although the size o the nuts

ormed is completel dependent on the emaleparent, the pollen parent infuences the favoro the nuts (Anagnostakis 1995a, Anagnostakisand Devin 1998).

Growers interested in getting nuts as largeas those o Japanese or European chestnut butwith the superior favor o American chestnutsstarted creating hbrids in the late 1800s. Aterchestnut blight disease began killing timber

A pure stand o American chestnut in Connecticut in 1910.

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24 Arnoldia 66/4

chestnut treesand Asianchestnut trees were seen tobe resistant to the diseaseit was hoped that new

hbrids could be developedthat combined the upright,timber-producing orm oAmerican chestnut withthe Asian species resis-tance to blight.

Arthur Graves, a plantpathologist in Connecti-cut, began crossing blight-resistant Asian trees andsusceptible American trees

in 1930. He then testedthese hbrids or resis-tance to chestnut blightdisease (Graves 1937). Hewas soon joined b DonaldJones o the ConnecticutAgricultural ExperimentStation (CAES), who was arenowned geneticist witha great interest in chest-nut. Man o those origi-nal hbrids are still alive,

and CAES now has what isprobabl the nest collec-tion o species and hbridso chestnut in the world.These were planted on landlet to the State o Connect-icut b Graves, and at theCAES arm, both located inHamden, Connecticut.

Trees with two ormsare being chosen rom our

continuing breeding eortsat CAES: tall, straight treeswith limited energ putinto orming nuts but verwell-suited or timber pro-duction, and short, spread-ing trees with maximumenerg put into orminglarge, good-tasting nuts,making the trees suitableor commercial or backardnut orchards. Both kinds o

This map shows the presence o chestnut blight disease in Connecticut in 1908.

Blight canker on an American chestnut tree; note the dead, sunken bark and lumps oungal tissue that have broken through the surace where the will orm spores.

SANDRA

ANAGNOSTAKIS

CLINTON1912

DISEASE NOT REPORTED

DISEASE NOT BAD

DISEASE BAD

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trees must have resistance to chestnut blightdisease and be well adapted to the New Eng-land climate (Anagnostakis 1992). There is nowinterest in developing DNA tests or geneticmaps o chestnut trees (http://www.agaceae.org/web/db/index), and we are using specic

crosses to stud the genetics o resistance to dis-eases as well as to develop timber and orchardchestnut trees.

To make these crosses, we put waxed paperbags over emale lowers in late June beorethe are ertile, then put selected pollen on thefowers in Jul and cover them up again. Thisallows us to know the parents o the nuts thatorm. During our breeding program we haveound that man hbrids that are the result ocrosses between two dierent species do notorm unctional pollen. These male-sterile trees

produce male catkins with fowers that neverbloom. Although this lack o pollen is a nui-sance in the breeding program, it is a eaturevalued b commercial nut growersthe canplant orchards o male-sterile trees with a ewpollen-producing trees and have ields o nuts

that are ver uniorm.When it became clear that at least two geneswere responsible or resistance to chestnutblight, we began a back-cross breeding programbased on the plan o Charles Burnham (Burnham1988). Asian trees are crossed with Americantrees, and the hbrids (partiall blight resistant)are crossed to American trees again. I thereare two resistance genes, one out o our o theprogen rom these back-crosses has one copo both resistance genes, giving it partial resis-tance. I there are three genes or resistance, one

American chestnut fowers on a tree near Quabban Reservoir in Massachusetts.

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26 Arnoldia 66/4

out o eight o the progen will have one copo all three resistance genes. Trees with partialblight resistance are crossed again to Ameri-can chestnut trees. This repeated back-crossingincreases the percentage o American genesin the hbrids, and selecting or partial resis-tance insures passage o the resistance genes. Anal cross o two trees with partial resistanceshould result in one o sixteen trees having twocopies o two resistance genes (or one o sixt

our trees having two copies o three resistancegenes), which will make them ull resistant tothe chestnut blight ungus.

Biological Control o Chestnut Blight Disease

In a 1992Arnoldia article we described viruses,called hpoviruses, that inect C. parasit-

ica and keep the ungus rom killing trees breducing its virulence (Anagnostakis and Hill-man 1992). Since 1972, when CAES imported

A row o twelve-ear-old chestnut hbrids selected or timber qualities.

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Percentage of American genes in back-crossed (BC) hybrid chestnut trees.

The densel spin chestnut bur encloses several nuts, tpi-call three.

American chestnut trees in this Hamden, Connecticut,orchard were treated with biocontrol strains rom 1978 to1981, and 15% o the 71 trees survive as the original trunks inspite o the presence o man cankers. Hal o the trees con-tinue to be in a repeating ccle o ding back and resprouting.About one third o the trees died back once, resprouted, andthe sprouts are still surviving.

PARENTS AMERICAN GENES HyBRID

1. American 100% American genes egg x + = 50% A F1

Japanese 0% American genes pollen

2. American 100% American genes egg x + = 75% A BC1

F1 50% American genes pollen

3. American 100% American genes egg x + = 87.5% A BC2

BC1 75% American genes pollen

4. American 100% American genes egg x + = 93.8% A BC3

BC2 87.5% American genes pollen

5. BC3 93.8% American genes egg x + = 93.8% A BC3-F2

BC3 93.8% American genes pollen

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28 Arnoldia 66/4

virus-containing strains o the chestnut blightungus rom Europe, great strides have beenmade in understanding how these viruses cankeep the ungus rom killing trees. The genes

o three kinds o these (dsRNA) viruses havebeen sequenced, and the viruses placed in thegenus Hypovirus b Bradle Hillman and hiscollaborators (Hillman et al. 1994). We havestudied the movement o both killing and cur-ing strains o the ungus b birds and insects oseveral kinds (Anagnostakis 1990; Anagnosta-kis 1995b; Anagnostakis 2001). Although wehave introduced hpovirulent strains o the un-gus into orest plots, this biological control hasnot brought about a general recover o orest

chestnuts in Connecticut. However, it has beensuccessul in an orchard o American chestnuttrees at the CAES arm in Hamden, Connecti-cut, where we introduced hpovirulent strainsinto ever canker that we could reach or ourears rom1978 to 1981. Now, although hal othe trees continue to die back rom chestnutblight (and sprout, and die back, etc.), about athird that died back once and sprouted now sur-vive and fower even though the are coveredwith cankers, and about 15% o the trees arethe surviving original stems.

Snthesis o Breeding and Biological Control

The crosses that have produced blight-resis-tant trees or timber have, b necessit, used arather narrow genetic base, even though dier-ent trees were used as parents in each genera-tion. At CAES, this has involved crossing andback-crossing both Japanese and Chinese chest-nut trees (C. crenata and C. mollis-sima) with locall adapted Americanchestnut trees. Our strateg has been

to keep native chestnuts alive andlowering b using our biologicalcontrol agent. This eliminates theneed to search or American treesthat have survived long enough tofower. It also lets us use populationsin specic orest clearings. B plant-ing resistant trees in the orests andtreating the native trees with ourbiocontrol, native trees will surviveto naturall cross with the resistanttrees and will incorporate blight

resistance and all o the native genetic diversitinto the uture generations. The rst generationospring will be intermediate in resistance, butsubsequent generations will produce trees with

ull resistance.

Chestnut Trees or the Orchard

In addition to selecting timber trees, we havecontinued to evaluate trees or their potentialor orchard production in New England. A ewacres o chestnut trees can produce enough nutsto sell at armers markets or to local stores.The onl serious pest is chestnut weevil, whichcan be controlled b spraing insecticide whenthe nuts are ripening, or b allowing chickens

or guinea owl to range under the trees and eatthe weevils and their grubs. Squirrel control isalso essential and ever nut armer has his orher own method.

The most productive chestnut orchards areplanted with named cultivars, which are vege-tativel propagated clones o the original namedtrees selected or ecient nut production. Sincecuttings o chestnut trees will not orm roots,chestnut orchard cultivars must be grated ontosuitable rootstock or propagation. Althoughthis increases the cost o the plants, the value in

having proven clones makes the purchase pricewell worth it.

Another challenge aced b growers is thatsome splendid cultivars that do well in one parto the countr do not do well in other places.For example, cultivars suited to the ar south orto the ar west ma not do well in New England.Selections rom Ohio have generall proven

A basketul o nuts rom a hbrid chestnut orchard.

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reliable in southern New England, as have theew cultivars released rom CAES. Since I amthe International Registrar or Cultivars oChestnut, inormation on new trees usuall

crosses m desk, and I keep a list o the namesused and some o their characteristics on ourwebsite (http://www.ct.gov/caes/cwp/view.asp?a=2815&q=376864).

The biggest challenge to development o anut industr in New England is the lack o anestablished marketman people have nevereaten chestnuts and are hesitant even to trthem. Also, man who have bought chestnutsand then had weevil larvae crawl out o themwill never bu them again. Eorts to develop

markets and grower awareness in Michigan andMissouri are making some progress and canserve as examples or New England.

The Next Problem

Even as progress was being made towardblight resistance, another serious chestnutpest arrived. The oriental chestnut gall wasp,Dryocosmus kuriphilus, was introduced intothe United States in 1974 b a grower whoevaded plant quarantine (Pane et al. 1976).The insect las its eggs in lea and lower

buds, resulting in deoliated trees with nofowers. Entomologist Jerr Pane chronicledthe devastation o orchards o Chinese chest-nut trees planted in the state o Georgia. Wehave reports o inestations throughout Ala-bama, North Carolina, and Tennessee, andmost recentl in Columbus, Ohio.

As a consequence, breeding work must nowinclude selection or resistance to this pest. JerrPane has observed that American and Chinesechinquapins (Castanea pumila, C. ozarkensis,

and C. henryi) are resistant to inestation, asare some cultivars o C. crenata. Once again,the CAES collection o species and hbrids isbeing used or making new crosses, and progenrom these crosses are being tested in NorthCarolina where the insect is now endemic.These trees were examined b Stac Clark othe United States Forest Service in 2006 andthe preliminar results were encouraging. O93 trees planted in 1995, there were 53 thatsurvived the droughts, deer, rabbits, and weedcompetition or 12 ears. Among the survivors,

Developing gall and damaged chestnut shoot caused bthe Oriental chestnut gall wasp.

11 had no wasp galls and 25 had ew galls. Wehope to understand how resistance is inheritedand will incorporate this resistance into ourtrees as quickl as possible.

The other ra o hope or dealing with gallwasp is that Asian parasites released b JerrPane seem to be moving with the wasp (Paneet al. 1976). Lnne Rieske recentl reportedthat parasites were now in the Ohio popula-

tion (Rieske 2007). I these parasites continueto improve as control agents or gall wasp, itis possible that onl stressed trees will be seri-ousl damaged b wasp inestation.

Whats Next?

We will soon have timber chestnut trees thatcan survive in New England. These trees willprovide another source o lumber and will alsoincrease the diversit o tree species in orests.We are learning about growing chestnuts inorchards in New England and selecting better

JERRyA.PAyNE,USDAAGRICULTURALRESEARCHSERVICE,BUGWOOD.ORG

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This 1905 photograph shows the tall, straight trunk o a then 103-ear-old American chestnut in Scotland, Connecticut.

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IMENTSTATIONBULLETIN154(1906)

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nut-producing cultivars to make a new nichecrop or armers.

The work goes slowl, but is ver satis-ing. When I talk to scientists who conduct

laborator research, and expect results withinmonths, the are oten astonished that I havebeen working at this research or more than 40ears. There are no quick solutions to the com-plicated problems in the environment, and treestake a long time to grow. When man actors areinteracting the must all be considered. We canmake crosses o our trees, wait 10 ears or theseedlings to mature, select them, make morecrosses, wait 10 ears, and still miss some cru-cial clue in the soil or the weather or animals or

insects that will aect our hoped-or outcome.When talking with students I tr to emphasizethe need or patience, keeping an open mind,and noticing everthing. Publish or Perishand More Grant Funding or Survival are stilldriving orces that tempt scientists to ocus onsmall things that can be examined in isolationand written up quickl or scientic journals orgranting agencies, but it is important to keeplooking at the big picture.

Reerences

Anagnostakis, S. L. 1990. Improved chestnut treecondition maintained in two Connecticut plotsater treatments with hpovirulent strains othe chestnut blight ungus. Forest Science 36:113124.

Anagnostakis, S. L. 1992. Measuring resistance o chestnuttrees to chestnut blight. Canadian Journal ofForest Research 22: 568571.

Anagnostakis, S. L. 1995a. Eect o the Male Parenton Nut Weight in Chestnut. Annual Reportof the Northern Nut Growers Association 86:124127

Anagnostakis, S. L. 1995b. The Pathogens and Pests

o Chestnuts. pp. 125145, In: Advances inBotanical Research, vol. 21, Andrews, J. H. andI. Tommerup, eds., Academic Press, New york.

Anagnostakis, S. L., and P. Devin. 1998. Lack o Eecto Pollen Parent on Nut Weight o Chestnuts.

Annual Report of the Northern Nut GrowersAssociation 89: 1517.

Anagnostakis, S. L. 2001. The eect o multipleimportations o pests and pathogens on a nativetree. Biological Invasions 3: 245254.

Anagnostakis, S.L. Chestnut cultivar names. http://www.ct.gov/caes/cwp/view.asp?a=2815&q=376864

Anagnostakis, S.L. Chestnuts and the introduction ochestnut blight. http://www.ct.gov/caes/cwp/view.asp?a=2815&q=376754

Anagnostakis, S. L. and Hillman, B. 1992. Evolution o

the chestnut tree and its blight. Arnoldia 52(2): 210.

Burnham, C. R. 1988. The restoration o the Americanchestnut.American Scientist 76: 478487.

Clinton, G. P. 1912. Chestnut bark disease. Report othe Station Botanist. 19111912, pp. 407413.

Annual Report of The Connecticut AgriculturalExperiment Station, New Haven, Connecticut.

Cogbill, C. V., Burk, J., and Motzkin, G. 2002. The orestso presettlement New England, USA: spatialand compositional patterns based on townproprietor surves. Journal of Biogeography29:12791304.

Graves, A. H. 1937. Breeding new chestnut trees.Annual Report of the Northern Nut GrowersAssociation 28: 93100.

Hawes, A. F. 1906. Chestnut in Connecticut and theimprovement of the woodlot. Bulletin 154, TheConnecticut Agricultural Experiment Station,New Haven, CT.

Hillman, B. I., Fulbright, D. W., Nuss, D. L., and Van Alen,N. K. 1994. Hpoviridae. In. Virus Taxonomy:Sixth Report of the International Committee

for the Taxonomy of Viruses. F. A. Murph, C.M. Fauquet, D. H. L. Bishop, S. A. Ghabrial, A.W. Jarvis, G. P. Martelli, M. P. Mao, and M.

D. Summers, eds. Springer-Verlag, Wein, Newyork.

Metcal, H. and J. F.Collins. 1909. The present status ofthe chestnut bark disease. Bulletin 141, part5, pp. 4553. U.S. Department o Agriculture,Washington, DC.

Pane, J. A., Green, R. A., and Lester, D. D. 1976. New nutpest: an oriental chestnut gall wasp in NorthAmerica. Annual Report of the Northern NutGrowers Association 67: 8386.

Pierson, A. H. 1913. Wood-Using Industries ofConnecticut. Bulletin 174, The ConnecticutAgricultural Experiment Station, NewHaven, CT.

Rieske, L. K. 2007. Success o an exotic gallmaker,Dryocosmus kuriphilus, on chestnut in theUSA: an historical account. EPPO Bulletin 37:172174.

Saucier, J. R. 1973. Natural range o American Chestnut,USDA Forest Service Fact Sheet 230.

Sandra L. Anagnostakis continues her research atthe Connecticut Agricultural Experiment Stationin New Haven. She is still having too much un toconsider retiring.

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American Chestnut: The Life,Death, and Rebirth of a Perfect TreeSusan Freinkel. Universit o CaliorniaPress, 2007. 284 pages.ISBN 978-0-520-24730-7

A

merican Chestnut: The Life, Death, andRebirth of a Perfect Tree chronicles the

histor o chestnut blight, a devastat-ing ungal disease irst identiied in 1904 bHermann Merkel, Chie Forester o the Newyork Zoological Park, and studied b WilliamMurrill, a mcologist at The New york Botani-cal Garden. The ungusreclassied in 1978as Cryphonectria parasiticaswept rapidlthrough American chestnuts native range,nearl annihilating this once-dominant treespecies. B mid-centur the blight had reachedthe southernmost part o the rangeAlabama,Mississippi, and northern Georgia. Freinkel

notes, A map produced b Gravatt in 1943showed the scope o the pandemic as a longellipse stretching nearl the ull length o theAtlantic seaboard. Within that ellipse, 50 to99 percent o the chestnuts were dead . . . Alltold, it is estimated the blight killed betweenthree and our billion trees, enough to ll ninemillion acres. That is enough trees to coveryellowstone National Park eighteen hundredtimes over.

Susan Freinkel presents ethnobotanical inor-

mation on the cultivation o the American or-ests, irst b Native Americans and later brural inhabitants. She describes an Appalachianculture beneting rom an econom based oncollecting chestnuts rom amil orchardsactuall chestnut stands in the wild that looselbelonged to dierent amilies b tradition orproximit. With little else to use as barter,Appalachian amilies used chestnuts in tradeor store goods at mountain exchange posts.

The trees carrot favored nut was consideredsuperior to other endemic nut species, and itslumber was straight, strong, and rot resistant.The Appalachian voices in this book providea soliloqu to the species, which was once soabundant that a squirrel could supposedl passrom Maine to Georgia in its branches.

The American chestnutin diminished

ormstill lives on more than one hundred earsater the blight was rst diagnosed. But the spe-cies is on a lie line, as the author details, waitingor a positive outcome rom the experimentalstrategies o back breeding and guided naturalselection. Freinkel conves the tale o Amer-ican chestnut through the acets o rural andsuburban culture, ocusing primaril on Appa-lachia, New york Cit, and Pennslvania. Shedetails the endeavors o the nascent orestr andagricultural departments, observant naturalistsand scientists, and well-intentioned legislators.

The book portras ke agents and events in theAmerican chestnuts struggle to survive.

Man o the chapters are dened b singu-lar people with some intuitive knowledge andskill who bucked common opinion in theirmethods. The were agents in earl controlmeasures like ungal identication, eventualexperiments to ght ungus with ungus, andlater breeding and scientic eorts to improvethe chestnut gene pool. This legac is mostlborne b a ew tenacious individuals, man o

whom receive well-deserved public recogni-tion in this book. The were the architects oexperimental nurseries and laboratories work-ing on breeding projects or ungal experimentswhose results are clocked in a lie ccle longerthan that o human generations. These eorts,not et abandoned, ma still succeed.

This wonderul book is paced like a msternovel, complete with ascinating characters.The plot line o chestnuts survival includes

Book Review:American Chestnut: The Life,Death, and Rebirth of a Perfect Tree

Heather D. Heimarck

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Book Review 33

serendipitous interventions such as that o across-countr skier turned horticulturist whorecognized a surviving stand o chestnut treesin Michigan, or the observant tourist who didhelpul comparative research on the Europeanchestnut blight. The histor also includesunortunate, oolhard visions borne o thespirit o the times such as seed irradiation or

the advice given to the strug-gling public to cut downever tree while the lumbervalue still ielded a proit.

The eects o such commerceconsequentl spread the blightand reduced the gene pool. Thestor o the American chest-nut showcases a chapter oscientic histor, human his-tor, and a change in environ-mental consciousness.

Susan Freinkel combinesan eas narrative stle with aactual et poetic voice that

elevates this material beonddr science to make it a com-pelling, addictive read. As theauthor points out, in a worldwhere a species is lost everminute, the survival and poten-tial comeback o the Americanchestnut is a victor song orthe unsung soldier. The beauto this book is that at its heartit is a tale o the heroic spirit oindividuals who have dedicated

careers to work on a solutionagainst great odds. Her obser-vations ocus the dialogue onthe evolution o a conscious-ness about an enem that hadnot been understood or appre-hended. It became an enemthat schooled oung oresters,botanists, ecologists, enthu-siasts, and scientists on howto work on a problem o vast

scope. To the authors credit,she rerains rom moralizing orpredicting the uture. She turns the problemaround or proper examination rom all sides.An old riddle is answeredes, i a tree alls inthe orest and there is no one there to hear it, itdoes make a sound.

Heather D. Heimarck is Director o the LandscapeInstitute o the Arnold Arboretum.

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2008 Weather at the Arboretum

The autumn o 2007

was so dr that alltransplanting had to

be postponed, so moisturewas a major concern as 2008arrived. Fortunatel, theear brought greater thannormal rainall which pro-vided optimum conditionsor our moisture-starvedcollections.

Januar was marked bwarmer than normal tem-peratures, including a balm65F on the 8th, and onlone snowstorm (on the 14thand 15th) which produced6 inches o snow, the totalor the month. Februarwas mild and wet with over8.5 inches o total precipi-tation including 15 incheso snow. Onl 2 inches

o snow were recorded inMarch, well below nor-mal, but rainall added upto nearl 6 inches. Aprilstarted warm, with somerain, but became dr as themonth progressed, causingconcern or the imminentspring transplanting season.Our concerns diminishedas we received 2 inches o

rain toward the end o themonth. Ma was quitedr with onl 1.5 inches orain, and irrigating our newplantings was a priorit aswe eared a repeat o the drsummer o 2007. ThoughMas total rainall was low,a string o das with brielate

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