THE ROCK SPLEENWORTS. 
manages to exist upon many shaly hillsides 
where the falling fragments are constantly 
crowding its fronds. 
The fronds are borne on very short 
stipes in tufts from a small rootstock. 
There is a noticeable difference between fer- 
tile and sterile blades. The latter are seldom 
more than six inches long and an inch wide % 
and spread close to the earth. 
They are once pinnate with close 
set, short, blunt and obscurely 
serrate pinnules eared on the su- 
perior side at base. The fertile 
are three or four times longer, 
stiffly erect, in marked contrast 
to the others. The pinnules are 
also much longer, often an inch 
or more in length, usually con- 
spicuously serrate and inclined to 
be eared on both sides at base. 
They are about linear-oblanceo- 
late, tapering acutely below and with pin- ‘ 
nules much farther apart than in the sterile 
frond. The rachis in 
both kinds of fronds is 
dark shining brown. The 
sori are borne ina double 
row on each pinnule at 
some distance from the 
margins. When young the white indusium 
is conspicuous, but it soon withers and the 
sori, becoming confluent, cover most of the 
under surface of the frond. The fertile 
161 
& 
OS 
dp 
ot? 
Raf? 
a a 
Px? 
Dy] 
Qo pO” 
Qf” 
Lm: oY 
oe 
t GE 
Dy Vy 
Ly Wy 
he 
Uy 
EBONY 
SPLEENWORT. 
Fertile frond. 
