THE ROCK SPLEENWORTS. 159 
borne on the backs of ordinary fronds, several on each 
pinnule and slightly nearer to the middle than the 
margin. The indusium, of course, is linear. 
In the eastern United States, the green spleenwort is 
found only in Vermont. Further north it is slightly 
more abundant and is generally distributed throughout 
British America, reappearing in our Western States in 
the mountains of Oregon, Wyoming and Washington. 
It is also found in Greenland and in the colder parts of 
the old world. Over seas this species grows with the 
maindenhair spleenwort and in our own country selects 
much the same habitats. It is occasionally called green 
maidenhair. We illustrate a Vermont specimen. 
The Small Spleenwort. 
The small spleenwort (Asplenium parvulum) is a south- 
ern species which careless collectors might gather for 
the maidenhair spleenwort or perhaps the ebony spleen- 
wort. It grows in tufts on shaded, or sometimes on 
sunny cliffs, the fronds spreading from a short half-erect 
rootstock. The stipe and rachis are very dark brown 
and polished but are much more rigid than in the maid- 
enhair spleenwort. The fronds are also thicker, almost 
leathery in texture and much broader. 
In shape the fronds are linear-lanceolate and once pin- 
nate with many pairs of opposite, oblong, blunt pinnules 
that are usually slightly eared on the upper side at base. 
In the larger fronds, which may occasionally reach a 
length of ten inches, there isa tendency to produce an ear 
on the inferior bases of the pinnules also. This is espe- 
cially noticeable in the shortened lower pinnules which 
thus often become triangular. The sori are borne on 
