80 Ebony Spleenwort 
manes. The color that replaces the green appears first at the 
petiole’s base and spreads upward, involves in time the entire 
rachis, and, occasionally, in the larger leaves, encroaches also on 
the under surface of the pinne, along the midveins. It is straw- 
color at first, but gradually becomes chestnut-brown or darker, 
finally shading from brown to ebony and, occasionally, tinged 
with green. 
Auricles at the bases of the pinne are absent in the first early 
stages of the leaf’s development, but a tendency toward especial 
development at the places where they are to appear later is early 
noticeable. For instance, in many of the pinne of very young 
leaves the midvein’s superior basal primary branch, which later 
forms the midvein of the superior auricle, is once forked, while the 
other primary branches are simple. The auricles gradually 
form as the leaf develops, sometimes at the inferior sides of the 
pinnz as well as at the superior. They are in reality incipient 
secondary segments of the leaf. 
Although the leaf-blade’s margin is sometimes subentire or 
merely undulate, a greater or less degree of incision between the 
primary branches of the leaf’s midveins, or at least a tendency to 
such incision, is noticeable in all stages of the leaf. It is obvi- 
ously carried to its fullest extent in the production of the pinne. 
In the pinnz themselves it is commonly shown merely by serra- 
tion or crenation or undulation of the margin, but sometimes it 
is carried far enough to render the pinne cleft, more or less 
deeply, into segments. 
The so-called “‘ var. serratum”’ Gray is based upon leaves 
with such cleft pinne. These leaves are not uncommon in 
large, luxuriant, fertile plants, and represent, apparently, the 
height of normal development of this fern’s leaf. They are 
