The group Peranemeæ, or Woodsieæ, is represented in the British Flora by two species of Woodsia, which are amongst the rarest and most curious of our ferns, and inhabit the crevices in our highest mountain tops. Their tufts of fronds are not more than two or three inches high, sometimes less, and the fronds themselves are lanceolate, and pinnate; in Woodsia ilvensis they have oblong and usually opposite deeply lobed pinnæ, whose under-surface is clothed more or less with jointed hairs and long attenuated scales. The sori in both species are circular, and situated at the extremity of the lateral veins. When young they are covered with an indusium, which opens at the centre, and forms a cup round the sori; afterwards it is divided into numerous jointed and usually incurved threads. The Davallieæ are mostly tropical and subtropical ferns. Their sori are submarginal, placed upon the tip of a vein or veinlet, and enclosed within a tubular indusium, which is either short and approaching to cup-shaped, or more or less elongated. In this group the stem assumes the form of a rhizome, often creeping extensively, and the fronds are articulated, falling off with a clean scar when they perish. Davallia canariensis is cultivated in most conservatories, and is known as the Hare’s-foot fern, from the stoutish scaly rhizomes resembling the foot of a hare. Somewhat allied to these are the Lindsæeæ, including Lindsæa and its allies; these have linear marginal sori, for the most part continuous, but sometimes regularly interrupted, in which state they approach some of the Davallieæ, Microlepia to wit. The indusium opens towards the margin of the frond, and the sori more or less connect the tips of the veins and veinlets. [Illustration: Fig. 61. Scolopendrium vulgare.]