574 Mr. Brown on Lyellia, Leptostomum, and Buxbaumia. 
ing the columella in several species of Splachnum ; and perhaps 
even the tympanum of Polytrichum may be of similar origin. 
But these characters of Leptostomum and Hymenostomum, though 
they do not appear to have been yet observed in any other mosses, 
may still perhaps be considered too minute for generic distinc- 
tions: and it must be admitted that were nothing to be obtained 
but the subdivision of an extensive natural genus it could not be 
necessary to have recourse to them. The divisions in question, 
however, are certainly not of that kind. 
The weakest part indeed of Hedwig's system is its bringing to- 
gether all those mosses that have a naked peristomium, and even 
including the greater partof them in the genus Gymnostomum ; while 
many of the species so associated are in real affinity much nearer 
to several other genera of the order having a simple or even a 
double peristomium. | ‘à | | 
= Thus Gymnostomum iieri funem: the PANIER of the pre- 
sent paper, has less the habit of the genus in which it is placed than 
of Weissia, to some of whose species, especially IV. affinis and £richo- 
des, it seems to approach even in the structure of its peristomium. 
Several species of that section of Gymnostomum, to which per- 
haps the genus should be limited, especially G. fasciculare, Bon- 
plandii, and Rottleri, can hardly be distinguished from Weissia 
 Templetoni*. 
% 
* Weissia Templetoni, along with a nearly related species found in New Holland, Fu- 
naria minor of Delile (Flor. Ægypt.), and perhaps also Weissia radians, may form a genus 
distinct from Weissia, and nearly related to Funaria, differing chiefly in the irregular burst- 
ing and evanescence of the inner peristomium, which in Funaria is regularly divided and ge- 
nerally persistent, though in some cases perhaps equally deciduous. In a variety of Weissia 
Templetoni, or a very nearly related species, vollected in 1800 in the county of Donegal, 
I have observed the outer peristomium to be not unfrequently wanting, even before the se- 
paration of the operculum ; a fact which, if hereafter confirmed, would establish its affinity 
to Gymnostomum fasciculare. 
Gymnostomum 
