4 H Boodle. — Anatomy of the Schizaeaceae. 
Finally the sclerotic central ground-tissue in the stem of 
Mohria finds its counterpart in the solenostelic A. mexicana. 
The structure of Mohria thus suggests that the genus is 
probably quite nearly allied to Anemia , but it shows some 
characters which suggest greater tendency to xerophytism, 
than is found in A. Phyllitidis. 
Judged structurally, Anemia and Mohria are less primitive 
than Lygodium and Schizaea ; and of these Lygodium , having 
a solid stele, should be the more primitive. The petiolar 
bundle of Lygodium , however, is concentric, which is probably 
not a primitive character. It must be remembered that the 
well-developed leaves of this genus are specialized for twining, 
and it is probably because of this, that the bundle forms a 
rounded cylinder instead of conforming more to the type 
found in the other genera. The form of the petiole-bundle 
may in its turn have determined the retention of the primitive 
type of stele, because a solid cylindrical stele would be suitable 
for the attachment of a similarly shaped leaf-trace. Hence 
the structure of the stem alone should perhaps not be taken 
as pointing to the genus being necessarily more primitive than 
Schizaea. It is interesting, however, to observe that Bower 
(’99, p. 44 ) found that among the Schizaeaceae Lygodium 
showed the largest sporangia and the largest output of spores, 
and that these characters generally indicate primitive nature. 
A comparison of the structure of the Schizaeaceae with 
that of the Hymenophyllaceae and of other Ferns will be 
reserved for the concluding part of this paper, on the 
Gleicheniaceae, but one comparison may be made here. 
The structure of some species of Anemia shows considerable 
resemblance to Loxsoma. Gwynne-Vaughan (’01, p. 94 ) re- 
gards these resemblances as insufficient to constitute a close 
relationship, and this appears to be the case ; but perhaps 
a closer relationship to the Schizaeaceae than to the 
Hymenophyllaceae is suggested. The facts may be stated 
thus : — the solenostele of Loxsoma resembles that of A. mexi- 
cana in the elements of the stem-protoxylem being scalariform 
and scattered, and also approximately in their position. The 
