LASTREA. 
119 
It proves, however, to be the old Polypodium cemulum of 
the last century, which name must be restored. 
This Fern is a moderate-sized and very elegant plant, 
of drooping habit, and possessing a crisped appearance, 
from the recurving of the margins of all the segments of 
the fronds. It grows from one to two feet high, and from 
its tufted stem produces a spreading circle of triangular 
arching fronds, the stipes of which, of about the same length 
as the leafy part, is thickly clothed with small, narrow, 
jagged, pale-coloured scales. The fronds are bipinnate, 
the lowest pair of pinnae always longer and larger than the 
rest, and the pinnules on the inferior side of the pinnae 
larger than those on the superior side. The pinnules are 
of oblong-ovate figure, and the lowest of them often divided 
again into a series of oblong lobes, for the most part 
decurrent, but sometimes slightly stalked ; the margin is 
cut into short spinous-pointed teeth. The veins of the 
pinnules are alternately branched from a sinuous midvein, 
and these veins give off two or three alternate venules, 
the lowest anterior one bearing the sorus. The exact 
ramification of the veins depends upon the degree in which 
the pinnules or lobes are divided. The fructification is 
distributed over the whole under-surface, the sori being 
