How to Know the Ferns

by S. Leonard Bastin

Polypodium phegopteris. The Beech Fern.

Polypodium phegopteris. Here the specific name is formed of two Greek words—phegos, “a beech,” and pteris, “a fern.” This is, of course, a rendering of the popular name, though why the species has been called the Beech Fern nobody seems to know. Certainly the species is not like a Beech, neither can it be said to grow in association with this tree. The Beech Fern or Mountain Polypody.

This species has a slender creeping rhizome from which arise the dainty light green fronds. The fronds vary from about six inches to a foot in length; the stipes is longer than the leafy portion, and is of a light green colour. The outline of the leafy part is triangular in form, and on either side of the rachis are the tapering pinnæ. At the top the frond is pinnatifid, whilst the lower pinnæ are deeply cut. A very distinctive feature of the Beech Fern is the way in which the lower pair of pinnæ point downwards away from the tip of the frond.

Nearly the whole of the underside of the frond bears the sori. These are placed quite near to the margins of the lobes of the pinnæ. Like all the Polypodies the clusters of sporangia have no indusia.

The Beech Fern cannot be called a common species, though it is often abundant in certain localities. It is much more frequent in Scotland than elsewhere, and may be looked for hopefully in almost any moist wood. It also occurs abundantly in some parts of the North of England. Unless the Beech Fern can be given a moist position it is not an easy plant to grow in the open garden. It is, however, successfully cultivated in the greenhouse. The plant dies down in the winter, and the new fronds do not appear until somewhat late in the spring.

Polypodium dryopteris. Here the specific name is derived from two Greek words—drus, “an oak,” and pteris, “a fern.” Here again it is not easy to see a resemblance between this fern and an oak, unless it be that the newly-developing fronds are in colour something like the delicate green of the tree when it is decked in its new foliage. The Oak Fern or Three-branched Polypody.

This plant has a thin creeping rhizome from which the fronds arise. The stipes is of a pale green colour, and it is usually longer than the leafy portion. Actually the frond is divided into three branches, each of which is triangular in shape and pinnate towards the base, becoming pinnatifid at the tip. The pinnæ are deeply segmented. The unrolling of the frond is a very novel feature of this Fern, each branch at this time appearing to be like a small coil of wire. In its early days the golden green colour of the frond is very much pronounced, but as the leaf ages a deeper tone is assumed.

The sori are disposed near to the margins of the lobes of the leaves, and these are circular and without indusia. The lower pinnæ of the Oak Fern do not point downwards, as is seen in the case of the Beech Fern.

The Oak Fern is common in many parts of Scotland, and is to be seen carpeting the ground of many a moist wood. It also occurs in England chiefly in the northern counties. In some parts of Wales it is to be found in plenty, but the species is said to be rare in Ireland. The Oak Fern grows in a damp and shady spot in the garden, though it is often more happy in a pot. The fronds of the plant die down in winter, and the fresh ones do not start until late in the spring.