Rockcap Fern

Rockcap Fern Ledge

Rockcap Fern

A winter day spent walking along a flowing brook reminded me that all is not frozen or decaying in the dead of winter.  Looking down from the rock ledges, there amid the orange-brown of curled beech leaves and fallen cedar tips, undaunted by the ice and snow I saw green ferns waving gently above the moving water.

During winter’s coldest days, ferns are long from the memory.  The savory taste of fresh crisp fiddleheads with a feed of brooktrout is a mere thought tantalizing the tastebuds.  Spring is still months away.

While the foliage on most ferns die back in the fall, the Common Polypody Polypodium virginianum is evergreen.  Also called the Rockcap Fern, it is found growing on rocks, ledges or decaying logs.  It is specially adapted to places where there is little soil.

Rockcap Fern

The Rockcap is described as being pinnate meaning that a frond has pairs of leaflets growing along the single stem.  The entire frond may be 4-10 inches in length and the longest leaflets are in the middle of the stem.

Here is a quick exercise to help in understanding the identifying features of the Rockcap Fern beyond its name.  Looking at the picture above, grab a pencil and paper and try to draw the overall outline of the frond.  Then cut around the overall shape.  Next, make single cuts along each side of the stem to create ‘pairs’ of leaflets that are opposite from the base to the tip.

Click here to compare the pinnate leaflets of the Rockcap Fern with that of other ferns.…..

Looking at the evolution of plants on the phylogenetic tree, we learn that ferns are the earliest of the vascular plants having first appeared during the Paleozoic Era about 400 million years ago.  From the ledge shown in the top picture, a person can almost imagine these early plants beginning to cover the rocks and boulders that lay strewn across an otherwise lifeless landscape.

We often think of mosses and ferns being part of the same group but they are not.  The mosses, one of which this Common Polypody is attached to on the rock, are part of an earlier group of plants called bryophytes.  They lack the vascular system and rigid cell walls that support upright growth of the Ferns.

Ruffed Grouse, Deer and other plant eating animals may feed on the Rockcap Fern, however even though it is green in color, it provides limited nutritional benefit in comparison with other winter food sources.

In my nature library, I found a book titled Ferns in their Homes and Ours by John Robinson, published in Boston in 1894, fifth edition.  The original copywright is 1878.  The introduction begins “Fern-culture in America has still the characteristics of novelty, although ferns have long been favorites in other lands; for some of our New-England species have been under cultivation in Old England for two hundred and fifty years.”

The book goes on to describe how to best collect ferns to make an indoor fernery.  There are plans for an aquarium-like container that is fully covered with glass to maintain a temperate climate for the success in cultivating the plants indoors.  There is a section on the potential hazards of unwanted pests coming into the home with the ferns and ways of managing the flies, aphids and unwanted bugs.

On the very last page he writes: ” fern-mania, which may be traced from its beginning across the ocean to its recent development in this country, is a hobby superior to most others: but he does claim, that, properly guided, it can be the means of stimulating pure and healthy exercise and study; and that, whether pursued in a scientific way or only as a pastime, it can , in any event, do no harm, but may be the cause of great and permanent good.”

I am certain John Robinson had not an inkling that his words would at the very least deliver a chuckle on a cold January day 120 years hence.

Leaves in Pond