3 r 5 
Vascular Anatomy of PIatycerium. 
leaf-trace in the axis and its origin may be followed for the succed- 
ing leaf (No. 2), which is inserted on the left of the axis (Fig. 3,1-24). 
Thus, in Fig. 3, 1-10, only changes preliminary to the separation 
of the leaf-trace are observable ; in Fig. 3, 10-20, the leaf-trace 
(No. 2) is in course of separation. Before the leaf-trace (No. 1) is 
cut off from the axis, one of the meristeles on the left divides into 
two, an internal and an external strand (Fig. 3, 7). This internal 
strand persists across the front of the leaf-trace, which appears 
as a ring of strands (Fig. 3, 1-6). The leaf-gap of the leaf 
(No. 1) has been filled by a long meristele, which also takes part 
in the formation of the leaf-trace on the left (Fig. 3, 8-10). The 
trace on the left (No. 2), at this point, begins to move out from the 
axis and the vegetative bud at the base of the leaf is formed from 
it (Fig. 3, 11-19). The sclerenchyma, meantime, forms a little 
pocket, and two of the strands give off the vascular supply to the 
bud, which passes into the pocket and is directed obliquely 
downwards. In Fig. 3, 77, 72, one of the meristeles on the right 
has divided to form the internal bundle of the still younger leaf 
(No. 3). Fig. 3, 20, 21, shows the leaf-trace on the left completely 
formed, but still remaining in communication with the main axis. 
An intrusion of sclerenchyma cuts off the leaf-trace finally, and 
the gap, as before, is filled by a meristele which appears long, since 
its course lies in the plane of transverse section. In the petiole, 
the number of strands in the circle increases by frequent division. 
An examination of the whole series of transverse sections shown 
in Fig 3, indicates that the origin of the leaf-trace thus described, 
is repeated for successive leaves. 
The anatomy of P. Willinckii, Moore, is like that of P. 
alcicorne. 
Platycerium cethiopicum is one of the largest forms in the 
genus. The leaves, which are very large, about li feet long, are 
of two kinds as in the other species, nest-leaves and foliage-leaves. 
The foliage-leaves are again divided into sterile and fertile leaves, 
the latter showing broad soral patches on the leaf expansions and 
also in the hollows between the expansions. The nest-leaves are 
large, deep brown when old, and show very distinctly the octagonal 
veining characteristic of the genus. The rhizome, which is 
ascending, is practically hidden by the nest and other leaf bases. 
It is extremely hard, due to the presence of much sclerenchymatous 
tissue. On the dorsal surface of the rhizome, the leaves are 
inserted in two alternating rows. After a set of nest-leaves has 
