There must be very few people, indeed, who are not familiar with the leading British representatives of the sub-family PolypodieÆ. It is difficult, indeed, to make a journey in any part of the country without sooner or later coming across some plants of the Common Polypody. Some other species of the genus Polypodium are not uncommon in certain parts of the country.

Polypodium vulgare. Here the generic name is derived from two Greek words—polys, “many,” and pous, “a foot.” This has been given to the plant on account of the fact that the creeping and branching rhizomes from which the fronds arise are in some way suggestive of feet. The specific name, of course, means “common.” The Common Polypody.

This species has a creeping root-stock which in its young days is covered with brown scales. From the underside there grow masses of fibrous roots, which often spread for a considerable distance. The rhizome may be very much branched, and from it alternately on either side arise the fronds. These may be quite short—about five or six inches—or, on the other hand, they may be as much as one or two feet in length. The stipes is usually about the same length as the leafy portion of the frond and is of a plain green colour. The general outline of the leafy part of the frond is lanceolate, tapering to a point, broad in the centre and narrowing slightly at the base. The frond of the Common Polypody is cut in a pinnatifid manner. The lobes, which are more or less rounded at the tip, are separated by openings in which the leafy portion is cut almost down to the rachis. Now and again the margin of the lobes is somewhat toothed.

On the back of the frond are to be found the sori. These are disposed on both sides of the mid-ribs of the lobes; they are circular in shape and have no indusia or covering of any kind. When the sporangia are young the sori are of a very pale yellow colour; this changes to a rich golden-brown as the capsules mature. The sori are mostly confined to the upper portion of the frond, and on account of their bright colouring add very much to the appearance of the leaf. There are a large number of varieties of the Common Polypody.

The Common Polypody will, of course, grow in almost any position. It often finds a home amongst the branches of old oak trees, whilst it seems to be equally happy on the wall or the hedge-bank. It is of fairly easy culture in the garden, though the plant likes a well-drained situation. The Common Polypody is an evergreen species.

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.

In some books a species called Polypodium calcareum (The Limestone Polypody) is described. In some quarters this plant is regarded as a variety of P. dryopteris, as it is similar in some respects. Mr. C. T. Druery considers it to be a distinct species. The chief points of difference are said to be the following. The whole plant is larger in growth, whilst the green of the fronds is not such a golden colour, even in the early days. Also the pinnÆ are not arranged so definitely in the form of three branches, as is to be observed in the case of the Oak Fern. Finally, the unrolling of the frond does not present the appearance of three little balls, seeing that each pinnÆ unfolds separately. The Limestone Polypody occurs chiefly in the North of England.

Polypodium alpestre. The Alpine Polypody. This is a most remarkable species, in that it bears a singular resemblance to the Lady Fern. By some authorities it is positively regarded as a Mountain form of the Lady Fern. The reason for linking the species with the Polypodies is found in the rounded sori, which have no indusia. The Alpine Polypody has a short tufted root-stock, and from this arise the fronds, which may be a foot or even more in height. The stipes is very short when compared with the leafy portion, and it is covered with brown scales. The general outline of the fronds is broadly lanceolate, and they are twice divided. The pinnÆ are arranged in alternation on either side of the rachis, and these are divided into pinnules with blunt points. The pinnules have toothed edges. The sori are chiefly situated near to the inside border of the pinnules. Those who consider that the Alpine Polypody is a form of the Lady Fern call the species Pseudathyrium alpestre.

The Alpine Polypody seems to be exclusively confined, as far as the United Kingdom is concerned, to the highlands of Scotland. It is sometimes to be found at an altitude of four thousand feet above sea-level. In spite of its restricted locality the Alpine Polypody is an easy subject for the garden, if it can be provided with a well-drained situation.