PREFACE. 
XV 
yields many marked nondescripts among Ferns. A plot of 
Pteris aquilina, on the roadside near a village, exhibited the 
stipes and rachis of the usual form and height, but almost 
wholly destitute of lamina and of fruit — a mere skeleton of 
the species. Branching forms of the Hart’s-Tongue are not 
seldom similarly defective ; and it may be said that, as a 
rule, the branching of the rachis implies the diminished 
breadth of the lamina. See our f. 9, of Scol. v. ramo mar- 
ginatum. 
But of all the changes to which the Lamina is subject, the 
bordering of the Hart’s-Tongue by a longitudinal process on 
both sides of the frond, and more or less regularly continued 
from its base to its point, deserves attention. See N.F., f. 597, 
and our f. 10. This bordering is usually divided from the 
Fig. 10 . 
