Some plant materials are woody and thick-ened, containing large amounts of lignin laiddown in cell walls. This provides mechanicalstrength and resistance to plant tissues since thelignin component is not easily degraded bymicrobial enzymes (much plant cellulose isencrusted with lignin and is therefore unavailableto many fungal species). These thickened tis-sues are recalcitrant to degradation and aremuch less easily broken down by fungi.Relatively few fungi are capable of lignin degra-dation but some species are efficient degraders(e.g. white rot fungi such as Phanerochaetechrysosporium, Rigidoporus ulmarius, Trametesspp) and these species can delignify plant cellu-lose. Fungi that cause wood rot without destroy-ing lignin are known as brown rots e.g. Serpulalacrymans. In the natural environment plantmaterials are usually colonised by a number ofdifferent fungal species and also by bacteria, and

Volume 11,Part 2, May 1997

the suite of microbial enzymes that are releasedby that population often results in efficientdecomposition of the plant debris.

It is clear that cellulases are also importantenzymes for plant pathogens, aiding entry intoand ramification through living plant tissues ,providing the proliferating mycelium with nutri-ents. However, some virulent pathogens effi-ciently enter plant tissues without causing agreat deal of disruption to the structural integri-ty and although these enzymes have a role toplay they are by no means the only determiningfactor in pathogenicity.

Susan IsaacSchool of Biological Sciences,

Life Sciences Building,University of Liverpool, Crown Street,

Liverpool , L69 7ZB

BOOK REVIEWSPatterns in Fungal development edited bySiu-Wai Chiu & D. Moore (1996). Pp . xii + 226.Hardcover. ISBN 0 521 56047 O. CambridgeUniversity Press, Cambridge, UK. Price £35($US 54.95).

This is an important and stimulating little book.Its eight chapters are based on a symposiumheld at IMC5 in Vancouver in 1994. They pro-vide an important but somewhat uneven contri-bution to facts and ideas on pattern formation infungi - a topic which mycologists have been slowto investigate experimentally. In this latterrespect, the first (Moore), sixth (Bourne, Chiu &Moore) and seventh (Frazer) chapters provideboth a useful summary of the facts available ondevelopment of the basidiocarp, particularly thatof Coprinus, and also a number of provocativeideas and hypotheses which need to be thoughtabout further and tested by experiment. Indeed,if the ideas developed in these chapters result inmore such work then the book will have morethan justified its production. Captivating ques -tions such as:

how are particular morphogenetic processesinitiated and sustained?

what is the nature of the postulated morpho-genetic fields and do they really have a

material basis?do fungal morphogenetic hormones exist, what

is their nature and how do they operate?how is coordination achieved in developing tis-

sues and within the developing basidiocarp?

are discussed within the very real limits of exist-ing knowledge. It is difficult to read about themwithout wanting to take these and related mat-ters further, both mentally and in the laboratory.Nor is the field mycologist neglected, forWatling's speculative chapter, embodying andsynthesizing a huge observational corpus as itdoes , suggests ways in which the form of basidio-carps in the wild are related to the conditions inwhich they grow and their functional require-ment to promote effective spore dispersal. Itbrings a dynamic view to the form, adaptationand function of the basidiocarp in nature.

The remaining chapters are less provocativesave perhaps that on hyphal tip extension andsubsequent development (Johnson, Calleja &Yoo). This is a salutary reminder that anyhypotheses to account for wall extension andgrowth need to encompass the phenomenon infungal unicells as well as hyphal forms. Thegenetics of morphogenesis in Neurospora(Vierula) adds little to what is already knownwhile those on pattern formation in the myceli-

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Volume 11, Part 2, May 1997

um (Klein) and nuclear changes during fungaldevelopment (Chiu) are frankly disappointingand not terribly clear.

The price at almost 15.5p per smallish pagemay seem a little high but fungal morphogenesisis so important and neglected and most of thebook so stimulating that no mycological library

The Powdery Mildews (Erysiphales) ofEurope by U. Braun (1995). Pp, ii + 337, illus.Hardcover. ISBN 3-334-60994-4. Gustav FischerVerlag, Jena, Germany & New York, USA. PriceDM 148.00.

Uwe Braun has succeeded in producing a com-prehensive inventory of European powderymildew fungi far exceeding the scope of a 'mere'flora. It is intended to serve as a general identifi-cation manual as well as a taxonomic treatise ofthese important plant pathogens. The book fullyaccomplishes these roles.

The publication in 1987 of the monograph ofpowdery mildews by the same author has beenused extensively in the present volume, and it istherefore not surprising to find many similari tiesbetween the two publications. A number of para-graphs and most descriptions of taxa throughoutthe book are repeated verbatim. The 'PowderyMildews of Europe' expands the informationavailable to the extent as to make this manual,in my view, the most thorough reference work onpowdery mildews in print.

The book is arranged in a systematic hierar-chical way with eight main sections subdividedinto a number of subsections. A brief prefaceleads to an extensive introduction featuring anhistorical survey of the Erysiphales and a discus-sion of morphological and anatomical features,both of the anamorphs and teleomorphs .Furthermore, both general biology and the taxo-nomic characteristics are presented. At the closeof the introduction the author provides a discus-sion on current theories of phylogeny and out-lines his species concept for the powderymildews .

A special part follows, providing keys anddescriptions to the 12 native European genera inbiosystematic order. At the beginning of the dis-cussion of each genus a key to species is includ-ed. The author recognises a total of 134teleomorph and 18 anamorph species (including

should be without it and any young (or old!)mycologist looking for a neglected and excitingarea in which to make a mark should read andact upon the ideas in this book.

John Burnett

one new species). Another key to species is prag-matically arranged in alphabetical order of hostfamilies. These keys are on the whole very easyto use, once the basic biology of the organisms isunderstood and providing the relevant fruitingstructures are present in the sample. Only veryfew 'blind alleys' have been found. The descrip-tions are comprehensive, listing all the relevanttaxonomic data (name, authority, publicationdetails , full complement of synonyms, majorillustrations and literature references , exsic-catae), the identity of type collections, generaland European distribution, and a concisedescription of the fungus with reference to theauthor's own illustrations. Unfortunately, theseare grouped in a separate section of the book.Some of the species are separated into a numberof varieties , leading in some instances to aplethora of information e.g . Erys iphecichoracearum with over six pages of detail!Whilst this might distract the applied biologistor the amateur, it provides a wealth of referenceinformation for the taxonomist. Further subsec-tions deal with anamorphs, doubtful records andexcluded species respectively.

The volume continues with literature refer-ences and illustrations. Each taxon described inthe main part of the book is accompanied by anillustration. The ink drawings are reproducedfrom the 1987monograph ·and were drawn by theauthor himself. Unfortunately the scale barlengths are not included with the plate captions.This should not, however, diminish the value ofthese excellent drawings (there is a reference toscale bar lengths with the abbreviations at thebeginning of the special part). The few electronmicrographs included are of poor quality. Asthey are insufficiently explained in captions ortext they do not appear to represent an essentialingredient and could have been omitted withoutloss.

The volume concludes with an index based onthe organisms described. There is also a section

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