154 
OBLONG WOODSIA. 
is scaly and articulated, or jointed, at a short distance 
from the base, so that in age the upper part with the 
fronds fall away, the lower part still adhering to the 
caudex. The fronds are seldom more than four inches 
high, oftener less; their form is lanceolate, varying 
in breadth, pinnate, the pinnae usually set on nearly 
or quite opposite in pairs, obtusely oblong, with the 
margin deeply lobed or pinnatifid. They are of a 
thick dull-looking texture, and are more or less 
clothed on both surfaces, but especially on the veins 
beneath, with minute bristle-like scales and shining 
jointed hairs, among which the sori lie almost con¬ 
cealed. The venation of the segments of the pinnae 
consists of a rather indistinct midvein, from which the 
smaller veins, simple or branched, extend to the mar¬ 
gin near which the sori are produced. The indusia 
are peculiar in that they are not placed as covers to 
the sori, but attached under them. When very young, 
indeed, they enclose them; but later they split- from 
above into narrow scale-like segments, not easily dis¬ 
tinguished without a glass from the frond-hairs among 
which they lie. In the full-grown state the sori lie in 
tufts of hair-like scales formed on the torn margins of 
the indusium, the latter being attached to the frond 
at the point beneath the capsules. No other native 
Ferns possess a structure at all approaching to this. 
