THE WOOD FERNS. 139 
undergrowth. Itis not generally distributed in its range, 
is often rare or missing over large stretches of coun- 
try, and is seldom as plentiful as marginale. It is easily 
cultivated and its stately fronds form a valuable addition 
to the fern garden. 
A form of this fern, from the Dismal Swamp has been 
described as the variety celsum. It differs from the type 
in being narrower, more erect and with pinnules and 
pinne further apart. 
The Crested Fern. 
When one’s rambles happen to take him through a 
piece of wooded swamp full of hellebore and skunk’s 
cabbage, where early in the season the marsh marigold 
and spring beauty cover the earth with bloom and later 
in the year the Canada lily hangs out its orange-yellow 
bells, he is likely to come upon the crested fern (A spzdtum 
cristatum) with its tall narrow fertile fronds quite erect in 
the dim light, as if disdaining the mud in which it is 
rooted. But thisisin summer. If one passes that way 
again in winter, no fertile fronds are to be seen, but the 
sterile still remain, fresh and green, though prostrate on 
the frozen ground and scarcely recognised as belonging 
to the same plant. 
Few species make a more striking distinction between 
sterile and fertile fronds. It seems to have the nature of 
two plants in one. The fertile fronds are tall, erect, and 
found only in summer ; the sterile are shorter, spreading 
and conspicuous only in the winter. In both, the outline 
is narrowly oblanceolate and acute, and both are pinnate. 
The pinnz are broadest at the base, the lowest pairs al- 
most triangular and the upper tapering outward to the 
tips. All are deeply cut into close, broad, obtuse pin- 
