The sori are placed on either side of the mid-veins of the pinnules, and these are usually confined to about half the upper portion of the back of the frond.
The Hard Prickly Shield Fern is very widely distributed in England, and it is to be looked for in shady woods. It is an exceedingly easy plant to grow, and thrives even in town gardens. The plant is evergreen in habit.
_Polystichum (Aspidium) angulare._ It is not regarded by some botanists as an established species, but is thought to be a variety of _A. aculeatum_. However, there are certain differences which appear to be specific. The Soft Prickly Shield Fern.
As in the Hard Prickly Shield Fern, we find a tufted root-stock from which grow lanceolate fronds. We notice the same short stipes and the narrow pinnæ on the leafy portion tapering to a point. In this species it is said that the pinnules at the base are more nearly equal in size than is the case with _A. aculeatum_. The pinnules are also more definitely stalked in the former than in the latter. In the case of the Soft Prickly Shield Fern, it is noticeable that all parts of the stalk of the frond--both stipes and rachis, and even the rachides--are covered with brown scales. It is said, too, that the droop of the fronds is more pronounced in the Soft Prickly Shield Fern than in the Hard Prickly Shield Fern.
The arrangement of the sori is similar in both species.
The Soft Prickly Shield Fern has been found widely distributed in England and Ireland, though it is not so common in other parts of the United Kingdom. It is easily cultivated, and is evergreen in habit.
_Woodsia hyperborea._ The generic name of this species commemorates the botanist, Mr. Joseph Woods; the specific name is taken from two Greek words--_hyper_, "beyond," and _Boreas_, "the north wind," without doubt a reference to the fact that the species extends to the Arctic regions. The plant is also called _Woodsia alpina_. The Alpine Woodsia.
This is a very pretty little Fern. The tiny fronds, which are not more than two or three inches in length, spring from a tufted root-stock. The stipes is rather short and bears a few brown scales. The outline of the frond is oblong, and the leaf tapers slightly towards the base as well as at the apex. The fronds are once pinnate, and the pinnæ, which are lobed, are arranged in rather an irregular fashion on either side of the leaf-stalk. A curious feature of the Alpine Woodsia is that the fronds are jointed just above their connexion with the root-stock. When the leaves die the stalks break away at this point and leave the bases behind.