Ferns of the Organ Mountains. Outline: 1.What are ferns? -features; life cycle; special...

Ferns of the Organ Mountains

Outline:

1. What are ferns?-features; life cycle; special characteristics like sori and gametophytes; desert adaptations

2. The Organ Mountains-a little geography and geology, and some of the habitats where you’ll find ferns.

3. Ferns in the Organs-some of the common ferns found in the Organ Mts. and where you might see them.

1: What are ferns?Ferns are plants that:

-have vascular tissue (unlike mosses and liverworts)

-have “true” leaves (unlike clubmosses, spikemosses, and horsetails)

-do not have seeds (unlike conifers and flowering plants)-do not have flowers (unlike flowering plants)

They reproduce via spores, produced in structures called sori (which we’ll see in a moment). These spores grow into a structure called a gametophyte; it’s called that because it produces gametes (sperm and eggs). When those gametes join, you get a new sporophyte (what we call the typical leafy plant that produced the spores, to distinguish it from the gametophyte).

Fern life cycle

sporophyte

sori on leaves

spores

gametophyte

sperm eggs

haploid (n)

diploid (2n)

(meiosis)

(fertilization)

Let’s not worry about diploid vs. haploid much for the moment. The general idea is that a sporophyte, what you’re used to thinking of as a fern, makes spores. The spores then grow into a gametophyte, which makes sperm and eggs. The sperm and eggs then join to form a new sporophyte.

Sporophyte

Gametophytes

R. Moran

Sori: why are they important?

Sori have a lot of variability between groups, and areoften very distinctive. So we use them a lot for

identification.

Gametophytes: why are they important?

Ferns are a bitlike amphibians.

Digression: frogs...

Adult frogs in desert areas fall into two categories:some, like spadefoot toads (left) can become dormantin dry periods; others, like leopard frogs (right) need

constant water.

Frogs, continued...

But, whether the frog is a spadefoot or a leopard frog, its tadpoles need constant water.

Sporophytes are like adult frogs

Though all fern sporophytes need water for active growth,like frogs they fall into two categories: those that live in

dry microhabitats and become dormant during dry periods, and those that can only survive in microhabitats that

provide constant water.

Gametophytes are like tadpoles

But, whether the sporophyte can survive drying or not, the gametophyte can’t.

It needs constant water to survive and a film of water for fertilization; if it dries, it dies.

So for desert ferns, the gametophyte is often thelimiting step.

R. Moran

Gametophytes 2

So how do ferns deal with the limitations of drought-intolerant gametophytes? Two main ways:

1. Have the gametophyte around for as short a time aspossible. While ferns from wet areas might have theirgametophytes sitting around for 3 months or more, desert ferns can go from spore to new sporophyte in as little as two weeks!

2. Give up on sex! If a fern can skip that pesky sperm/egg part, it can get to the sporophyte stage more quickly and doesn’t need a film of water for fertilization.

2. The Organ Moutains

This is a NASA satellite image

The Organ MountainsThe figure at right shows a simplified view of the geology of the Organs.

Purple is rhyolite, avolcanic, greyish rock.Blue is limestone, asedimentary rock thatforms in oceans.Red is quartz-monzonite, a kind ofgranite.

Different rocks, different ferns!

The Needles: granite.

The best fern habitats in the granite part of the mountainsare rocky, relatively moist slopes with occasional seeps

that have water most of the year.

Bishop’s Cap: limestone.

Bishop’s Cap has dry, gravelly slopes and ravines; a few ferns can survive on the slopes, others are

limited to sheltered microhabitats.

La Cueva & Dripping Springs: rhyolite.

The rhyolite areas offer steep, narrow canyons. Theseprovide areas of constant water that some ferns need and a wide range of good rocky outcrops and slopes.

3. Ferns in the Organ Mts.Aspleniaceae: ? Asplenium palmeri ?

Asplenium resiliensAsplenium trichomanes

Dennstaedtiaceae:Pteridium aquilinum

Dryopteridaceae:Cystopteris reevesianaDryopteris filix-masPhanerophlebia auriculataWoodsia cochisensisWoodsia neomexicanaWoodsia phillipsiiWoosdia plummerae

Pteridaceae:Adiantum capillus-venerisArgyrochosma limitaneaAstrolepis cochisensisAstrolepis integerrima

Pteridaceae, cont.:Astrolepis sinuataAstrolepis windhamiiBommeria hispidaCheilanthes bonariensisCheilanthes eatoniiCheilanthes feeiCheilanthes fendleriCheilanthes lindheimeriCheilanthes tomentosaCheilanthes villosaCheilanthes wootoniiCheilanthes wrightii

? Cheilanthes yavapensis ? ? Notholaena grayi ?

Notholaena standleyiPellaea atropurpureaPellaea intermediaPellaea truncataPellaea wrightiana

The short version: 31 ferns definitely in the Organs, 3 might be;4 families of ferns in the Organs, Pteridaceae (brake family) withthe most species.

Ferns and geology.Aspleniaceae:

Asplenium resiliensAsplenium trichomanes




Pteridaceae, cont.:Astrolepis sinuataAstrolepis windhamiiBommeria hispidaCheilanthes bonariensisCheilanthes eatoniiCheilanthes feeiCheilanthes fendleriCheilanthes lindheimeriCheilanthes tomentosaCheilanthes villosaCheilanthes wootoniiCheilanthes wrightiiNotholaena standleyiPellaea atropurpureaPellaea intermediaPellaea truncataPellaea wrightiana

Purple: occurs on rhyolite; Orange: occurs on rhyolite and granite; Blue: occurs on limestone; Green: occurs on limestone and rhyolite/granite.

Ferns and geology, cont..

Aspleniaceae:Asplenium resiliensAsplenium trichomanes





Purple: occurs on rhyolite; Orange: occurs on rhyolite and granite; Blue: occurs on limestone; Green: occurs on limestone and rhyolite/granite.

Notice: the rhyolite areas have the mostferns, and seven of them don’t occur in other parts; no ferns occur only on granite but a lot occur on rhyolite and granite; fourferns occur only on limestone.

Fern familiesSo, I told you sori are useful in identification, and here’s the proof... we’ll look at the three families you’re likely to see in the Organ Mts.

Aspleniaceae (spleenwort family)In this family, the sori are ovalor linear, witha flap (called theindusium) along one side.

These fernsrequire nearly constant moisture.

Dryopteridaceae (shield fern family)

In this family, the sori are round, with that flap (indusium), forming a shield or cup-like structure.

These ferns alsorequire nearly constant moisture.

Pteridaceae (brake family)

In this family, the sori form lines alongthe edges of the leaflets, protectedby the edge of the leaf or unprotected.

These are the truearid-dwelling ferns,living in the driesthabitats.

Pteridaceae, cont.

Aspleniaceae:Asplenium resiliensAsplenium trichomanes





Just a reminder:most ferns in the Organ Mts. are inPteridaceae; no surprise given that it’s the mostdrought-tolerantof the families.

So, now I’ll go through the three major parts of the Organs and show you some ferns you’d see there. Let’s start with Bishop’s Cap (A Mt. is similar).

Astrolepis cochisensis (Cochise cloak fern): most common fern on dry limestone.

Astrolepis integerrima (hybrid cloak fern): also ondry limestone

Cheilanthes feei (Fee’s lip fern): under overhangs, locally moist limestone.

In the granite portion of the mountains, you can see a number of ferns at Aguirre Spring

Cheilanthes fendleri (Fendler’s lip fern): common incracks in granite

Cheilanthes eatonii (Eaton’s lip fern): usuallyunder or between granite boulders

Cheilanthes eatonii (Eaton’s lip fern): usually under or between granite boulders

Pellaea truncata (spiny cliff-brake): amidgranite boulders, lower elevations

Woodsia neomexicana (New Mexican cliff fern): in moist soil or under granite boulders

Woodsia phillipsii (Phillips’ cliff fern): in moist soil or under granite boulders

And, last, let’s consider some of the ferns you’d near at Dripping Springs; we’ll see many of these on the next

field trip!

Some will be the same as what we’d see at Aguirre, butothers won’t.

Notholaena standleyi (star cloak fern): in cracksin exposed rhyolite

Cheilanthes bonariensis (golden lipfern): occurs inmoist soil near pools and seeps

Pellaea atropurpurea (purple cliffbrake): occurs inrocky soil under oaks

Pellaea wrightiana (Wright’s cliff-brake): found in cracks in exposed rhyolite & among boulders

Astrolepis sinuata (wavy cloakfern): occursin rocky soil on moist slopes

Phanerophlebia auriculata (eared veinfern): occursunder boulders in the moist bottoms of steep canyons

Asplenium resiliens (maidenhair spleenwort): occurson moist rock in seeps

Asplenium trichomanes (maidenhair spleenwort): occurson moist rock in seeps

Shameless self-promotion:

Want to see more pictures of ferns and other local plants? Well, I have a website:

www.polyploid.net

or:

www.newmexicoflora.com

Ferns of the Organ Mountains. Outline: 1.What are ferns? -features; life cycle; special...

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