Maidenhair 35 
or the smaller sublunulate, yellowish-brown, slightly striate; at 
margin whitish, thin, membranaceous, somewhat erose or slightly 
denticulate. 
Spores spheroid-tetrahedral, the three radiating angles marked 
with slender vittee or bands. 
Habitat. Rich woods, shaded banks, etc. 
Range. Nova Scotia to British Columbia, south to Georgia, 
Mississippi, Arkansas, Kansas, Utah, and California. Also in 
Alaska. 
Adiantum pedatum. Linneus, Sp. Pl. 1095. 1753. 
THE petioles and rachises of Adiantum pedatum are dark- 
colored in all stages of development. In the earliest stages 
they are hair-like. 
The leaf-blade is simple at first (Pl. II, Fig. 1a, a). It 
soon develops into a blade consisting of a single rachis leaf- 
let-bearing at sides and apex (Figs. 2-6). First one and then 
the other of the two basal leaflets on this rachis then develop 
into a branch, which consists of a similar leaflet-bearing rachis 
(Figs. 7b, c; 8’, c’). The outer basal leaflet (Fig. 8d) of the 
first branch (Fig. 8 6’) then develops likewise into a branch (PI. 
III, Fig. gd’). In this way the earliest dichotomous leaf-blade is 
formed (Pl. III, Fig. 9). This may be said to consist of a di- 
chotomous rachis (Fig. 9 e’ o’ 7’) bearing two pinne at each of 
its two apices. 
The leaflet that was formerly the inner basal leaflet g of the 
branch 0’ in Fig. 8 (Pl. II), becomes, when the outer basal leaflet 
d in Fig. 8 develops into the branch d’ in Fig. g (PI. III), the 
leaflet g’ on the section e’ o’ of the dichotomous rachis e’ o’ 7’ in 
Fig. 9, since e’ o’ in Fig.g corresponds to e o in Fig. 8. As no 
