28 BRITISH FERNS. 



lience this Fern is said to be subpinnate, which, in this case, 

 means partially pinnate, or pinnate at the very base only. The 

 pinnae have a narrow and acutely lance-shaped outline, and 

 are deeply pinnatifid ; they usually stand opposite each other 

 in pairs, the lowest pair being directed downwards, towards 

 the root, and set on at a short distance from the rest. The 

 united bases of the pairs of the other pinnae, when they hap- 

 pen to stand exactly opposite each other, exhibit a cross-like 

 figure more or less obvious ; and by this mark, in conjunc- 

 tion with the triangular outline and subpinnate mode of di- 

 vision, this species may be known from the other British 

 Polypodies. The veins in the lobes of the pinnae are pin- 

 nate ; that is to say, there is a slender midvein, from which 

 alternate venules, mostly unbranched, extend to the margin, 

 those near the base of the lobes bearing each one small cir- 

 cular sorus near their extremity the fructification thus be- 

 coming almost marginal. 



This is a somewhat fragile plant, enduring no longer than 

 till autumn, or the appearance of the first frosts. It grows 

 wild in moist mountainous situations and in damp woods, 

 often common enough where present, but rather limited in 

 its range ; occurring however in England to the southward, 

 westward, and northward; pretty generally distributed in 

 Scotland ; but rarely met with in Ireland. 



It is a very delicate and graceful Fern for pot-culture or 

 for a Wardian case, and requires plenty of percolating mois- 

 ture. On the damp, shady sides of sheltered artificial rock- 

 work, in the open air, it grows with tolerable vigour. 



SMOOTH THREE-BRANCHED POLYPODY, OR OAK-FERN. 



This species is named Polypodium Dryopteris by botanists. 

 It is sometimes, but less frequently, called Lastrea Dryopteris, 

 Polystichum Dryopteris, Gymnocarpium Dryopteris, and Phe- 

 gopteris Dryopteris. 



The fronds of this delicate little Fern grow from a slendei 

 creeping stem, which often forms densely matted tufts. 

 They are quite smooth, and of a bright light green colour, 

 supported by stipes, which are usually about twice as long 

 as the leafy part, and are slender, brittle, and dark-coloured. 

 The outline is almost pentagonal, the frond being divided 

 into three branches, each of which is of a triangular form. 

 One peculiarity about this species, which is in a slight de- 

 gree shared by its near ally P. Robertiamim, is the deflexion 

 of the rachis at the point where the lateral branches of the 



