Parts of Fructification in Mosses. 319 
firmly cohering with the teeth by the inner side of their apices. 
It dogs not therefore properly belong to the operculum, though 
in some cases it may adhere to it, as does the analogous process 
of the columella in Dawsonia and in several other Mosses. — 
The affinity of Dawsonia to Buzbaumia is certainly less strict ` 
than to Polytrichum, and rests chiefly on the similarity of the 
figure of the capsule, and in the central process of the colu- 
mella, which is still more evident in Burbaumia, where it forms 
part of the Linnean generic character, though unaccountably 
overlooked by Schmidel in his masterly dissertation ; but, if I 
mistake not, actually represented by him [in fig. 14, b, Z. c.], 
and confounded with the peristomium, which in this case, I 
suppose, had adhered to the operculum, as I have repeatedly 
found it to do, and thus escaped his notice. Hedwig consi- 
ders the plaited membrane which constitutes the peristomium 
of Buabaumia, as derived from the inner membrane of the 
capsule, and quotes the figure just mentioned of Schmidel in 
proof of this origin. In both species, however, I find it arisiag 
from the exterior membrane, though considerably within its 
margin, which in Buabaumia aphylla is said by Hedwig to be 
divided into teeth,—an appearance I could not observe in the 
few ripe capsules I have dissected. In other respects, the two 
species seem essentially to agree, and therefore ought not to 
be separated, as Ehrhart and some late writers have done. 
The generic character comprehending botb, ] would propose 
to alter in the following manner. se dan 
BUXBAUMIA. 
Capsula obliqua, hinc convexior, v. gibba. 
Peristomium intra marginem, quandoque dentatum, membran: 
exterioris ortum, tubulosum, plicatum, apice apertum. 
243 LEPTO- 
