Nature Journal: A good time to check out ferns

George Ellison | Nature Journal

When conducting plant identification classes, I sometimes bring along an assemblage of plants that demonstrates the different plant categories one can encounter in Western North Carolina.

On the one hand, there are the "vascular" plants: trees, shrubs, vines, grasses, sedges, rushes, herbs (the often showy, soft-stemmed plants like the violets, orchids, etc.), ferns, clubmosses, spikemosses, quillworts, and horsetails. Unlike the "non-vascular" plants (algae, fungi, lichens, liverworts, hornworts, and mosses), the “vascular” plants have xylem (supporting and water-conducting tissues) and phloem (food-conducing tissues) and usually reproduce by seeds.

I like to arrange examples of each of these categories on a long table so that participants can view a sample of each in sequence, from the most primitive to the more advanced. Many have commented that they appreciate seeing horsetail, liverwort, hornworts, and other “obscure” plants labeled so they can then look for them on their own in the wild.

I have pressed or dried specimens of all of these plant types – which I think of as "props" - that I lug along with me. Whenever I lay them out, it always occurs to me that the ferns are really an in-between group; that is, they are "modern" or "advanced" in that they have vessels that provide support or transport fluids, but they are "primitive" in that they still reproduce by spores rather than seeds.

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Gale Lawrence, in a delightful little book titled "A Field Guide to the Familiar" (1984), puts it this way: "Ferns occupy a place on the evolutionary ladder somewhere between primitive plants, which are still dependent on water for some phases of their life-cycles, and modern plants, which have become completely adapted to land."

One of my favorite times to observe ferns is in winter or very early spring when they stand out in the brown leaf-litter or on gray rock walls. Whenever out with a group walk in winter, the evergreen fern I can always count on finding is Christmas fern (Polystichum acrostichoides), which occurs in rocky woods or on cut banks. It is the most common evergreen fern in WNC. They grow in bouquet-like clusters from a scaly rhizome. The fiddleheads (emerging ferns) that appear in spring are covered with silvery scales. The mature green fronds can be up to 28-inches in length.

The fertile, spore-producing fronds of Christmas ferns are narrow at their tips. Look on the underside of a fertile frond tip and you'll see the clusters of cases in which the dust-like spores develop. Many Christmas fern fronds are simply vegetative and don’t display the narrowed tips or spore cases.

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The patterns in which spore cases are arranged is often the essential clue used to differentiate various similar fern species. But identifying Christmas fern doesn't require that sort of scrutiny. It is readily identified by the distinctive shape of the leaflets (pinna) that make up the vegetative portion of the frond.

Each leaflet resembles Santa's sleigh when viewed on a horizontal plane or a Christmas stocking when held vertically. This holiday motif is sounded again in the common name "Christmas fern," which arose because the species was used by the earliest New England settlers for Christmas decorations. They are still frequently cut or used as potted plants for seasonal arrangements.

What I see, however, whenever I arrange my pressed Christmas fern “prop” on the table with the other types, is an example of the plant type that dominated the world millions of years ago in often gigantic forms, paving the way for the seed-bearing plants that dominate our forests today. Ferns, which developed vascular tissue but still reproduce by spores, go right in the middle of the table between the "primitive" (non-vascular) plants and the "modern" (vascular) plants.

George Ellison is an award-winning naturalist and writer. His wife, Elizabeth Ellison, is a watercolor artist and paper-maker who has a gallery-studio in Bryson City. Contact them at info@georgeellison.com or info@elizabethellisonwatercolors.com or write to P.O. Box 1262, Bryson City, NC 28713.