116 ENGLISH BOTANY. 



shaped lanceolate, more attenuated towards the apex than towards 

 the base, bipinnate ; lower pinnse deflexed, upper ones spreading and 

 more distant ; pinnules narrowed at the base, inciso-serrate ; lobes 

 toothed at the apex ; ultimate veins running into the teeth. Sori 

 distributed over the basal half of the frond, the apex being destitute 

 of them, placed on the first anterior branch of the veins running 

 into the pinnules or on several of the branches. Indusium very 

 minute, very finely lacerate, fugacious, but rarely absent when the 

 fronds unfold. Spores brown, tuberculate, with rather numerous 

 small blunt irregular tubercles. 



Very rare and local. At the head of Glen Prosen, Clova, Forfar- 

 shire. Great Corrie on Ben Alder, Inverness-shire. 



Scotland. Perennial. Summer, Autumn. 



Fronds 3 to 12 inches long, with an extremely short stipes; in 

 cultivation the stipes is often confined to the enlarged basal portion 

 which remains attached to the caudex. Scales more numerous and 

 more of them ovate-triangular than in A. eu-alpestre. Lamina nar- 

 rower — in wild specimens from Ben Alder collected by Dr. Buchanan 

 White, with lamina between 3 and 4 inches long, the breadth is from 

 1 to 1£ inch at the broadest part, which is about one-third above the 

 base. Pinnules narrowed towards the base, while in P. eu-alpestre 

 they are broadest towards the base. The most remarkable feature in 

 this Fern is that the sori appear not to be produced on the apical 

 portion of the frond, they are most numerous in the basal third, and 

 it is but rarely that any can be found in the apical third. 



I have great hesitation in separating this as a subspecies from 

 A. eu-alpestre, because the character of the basal part of the frond 

 being soriferous and not the apex, is so unusual among Ferns, that 

 it may be suspected to be an abnormal form or monstrosity, and as 

 this I should have regarded it had Mr. Backhouse's original station 

 in Glen Prosen been the only one in which it occurred. But the Ben 

 Alder specimens are similar, and in cultivation the plant becomes 

 even more dissimilar from A. eu-alpestre than the wild specimens. 

 I have had cultivated plants from Glen Prosen, where I believe it 

 is now almost extinct, from Mr. Backhouse, and from Ben Alder from 

 Mr. A. Craig Christie and Dr. F. Buchanan White. Mr. A. C. Christie 

 tells me that A. flexile fruits when only 3 inches long, and A. alpestre 

 growing with it not under 9 or 10 inches. 



Dr. P. Buchanan White, who is one of the few botanists who have 

 published detailed descriptions of A. eu-alpestre and A. flexile, after 

 having observed both forms in their native localities, says, in the 

 'Scottish Naturalist,' 1881, p. 45: "The general appearance and 

 habit of flexile afford one of the best points of distinction. Aljje^frc 



