122 
BEAUTIFUL FERNS. 
times nearly two inches long. The base is either truncate or 
slightly cordate; sometimes where there is a transition from 
compound to simple pinnae, a pinna will be found conspicu- 
ously auricled on both sides, or on the upper side only. 
Forked pinnules are occasionally seen. 
The margin is continuously recurved to form a rather 
broad involucre, and the very edge is somewhat thinner and 
whiter. The veins are pinnately arranged on both sides of 
the midvein, and fork about twice before reaching the mar- 
gin. The upper part of the veinlets is covered with spor- 
angia, which as they ripen push out from beneath the 
involucre. The spores are obscurely tetrahedral and trivittate, 
as in the other species of the genus. 
This fern very often grows in company with Camptosorus 
rhizophyllus, and its root-stock is often hidden beneath mosses 
of the genus Anomodon: it takes kindly to cultivation, 
especially if it be planted in the crevices of calcareous rock- 
work. It may occur on other than calcareous rock, but I 
have never seen it on either granite, sandstone or basalt. 
Names for varieties of this species have been proposed 
by Pursh, and by Fournier, but the characters assigned do 
not seem sufficiently distinctive. 
