Club-Mosses on the mountain

A few days ago I had the opportunity to be a guest speaker on an alpine botany field trip for a class a friend of mine is teaching.  The highest and largest alpine environment in Vermont is atop Mt. Mansfield, two hundred acres of exposed rock, lichens, and a delicate assortment of tiny plants bordered by dense krummholz forest housing several rare bird species.

Mt Mansfield ridge trail

This areas is one of only three tiny regions of Vermont where alpine tundra environments exist, and part of a very small handful of places on the East Coast.  These places are relicts from the end of the last ice age, extremely sensitive to changes in temperature and moisture, home to plants that are usually found much further north.  The growing season is short, nutrients are in short supply, and wind stresses are high, all of which result in slow growing, long lived plants that do not colonize open areas well.  Visitors are encouraged to walk only on the rocky areas, keeping off of the easily damaged vegetation.

I had been eager to visit the peak of Mt. Mansfield for some time because it is one of the only places in Vermont that a certain small clubmoss lives.  I mentioned this to the botany students and during a rest break one of them got my attention and asked if the little plant he was pointing to was the one I had mentioned.

Appalachian Fir-Clubmoss (Huperzia appalachiana)

It was one of the smallest examples of Appalachian Fir-Clubmoss (Huperzia appalachiana) that I had seen anywhere, but it was indeed the plant I was looking for.

Clubmosses are really cool and predate flowering plants by an embarrassingly large span of time.  They are not really moss of any type, though they bear a superficial resemblance to the true mosses.  Mosses themselves are not true plants, having no vascular tissue, the plant equivalent of our circulatory system.  Mosses rely on diffusion to distribute water and nutrients and this imposes strict limits on their size.  Clubmosses are more akin to ferns and conifers: they have simple hair-like roots (true mosses have no roots), they have vascular tissue, and, at one point in the extremely distant past (300+ million years ago), their close cousins were the dominant large vegetation reaching one hundred feet above the ground.  Now most clubmosses are small, only a few inches tall, although in the Amazon I did encounter one waist high clubmoss near an overgrown pond.

Unknown Peruvian clubmoss. It grew to just above my waist.

I was interested in the Appalachian Fir-Clubmoss, Huperzia appalachiana, because several years ago I spent a summer in Shenandoah National Park, Virginia, climbing about on steep cliffs looking for this plant and trying to figure out how to measure any change populations might experience as the climate changes.  It likes acidic, well drained soils over igneous (or highly metamorphic) bedrock that receive frequent moisture, and, unusual for a clubmoss, direct sunlight.  It hybridizes easily with several other clubmosses, Shining Clubmoss (Huperzia lucidula), Northern Fir-Clubmoss (Huperzia selago), and Huperzia appressa, which some people do not distinguish from Huperzia appalachiana, making the identification question particularly vexing where the ranges overlap.

The Huperzia genus was recently split from the Lycopodium genus, which is where many of the more familiar clubmosses reside.  Like many of the Huperzia, the Appalachian Fir-Clubmoss grows from a dense basal cluster and, unlike many of the Lycopodium, it does not creep about over the ground.

Huperzia appalachiana – note the bands of white spore capsules

No-one is certain how long Appalachian Fir-Clubmoss lives.  The best answer I could get from a sharp fellow at Miami University in Ohio was, “At least seventeen years.”  Not a very satisfying answer, and he knew it.

One way to estimate the age is to count the bands of spore capsules on the stalk, those little white bits that looks like tiny eggs or pale ticks in the image above.  Each band correlates to roughly one year of growth.  Unfortunately, no-one knows how old the plant has to be before it starts producing those, and they don’t always produce them each year.  With some Huperzia species you can count the rings of gemmae, odd little cup-shaped brackets the plant produces that contain a tiny asexually produced plant that is dropped onto the ground in place of a spore when conditions are good.  The gemmae look very different from the microphylls, which is what clubmoss leaves are called.

Huperzia appalachiana
The gemmae are the little 3-part flanges near the top of the plant – further down the empty brackets are visible

Another way to judge the age is to count the bands of vegetation where the microphylls are pressed up close to the stem and where they spread out.  Each spreading ring indicates spring growth.

All that is good in theory, unfortunately Appalachian Fir-Clubmoss produces gemmae in a haphazard fashion and, unlike the photo above, often does not have those nice alternating bands of growth.  Hence the, “At least seventeen years,” answer to my question.

Clubmosses grow in a variety of forms and have been used for some rather unlikely purposes in the past.  The spores they produce are tiny and highly flammable, so much so that they were used as flash powder in old time photography.  Condoms were dusted with clubmoss spores to keep the rubber from sticking to itself, and diapers are sometimes dusted with the spores to prevent rashes.  Today, we mainly use living clubmosses in garlands and ancient clubmosses in our coal burning power-plants.

One of the great things about living in New England is the wonderful variety of local clubmosses.  They are delightfully archaic.  Deceptively so, considering that they have been living for well over 300 million years and are still common in many places world-wide.

Tree Ground-Pine (Lycopodium dendroideum)


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