THE GENEKA OF MOSSES. 
51 
one is a variety of a Gymnostomum, and the other an Ortho- 
tricum. Upon the whole, there are scarcely more than 
twenty-nine or thirty true species known of Gymnostomum^ 
including those described by Dr Hooker in Muse. Exot., 
(with the exception of Mr Brown's Leptosfoma^ which 
we conceive to form an excellent genus). In Great Britain, 
Sir Ja.mes Edward Smith enumerates sixteen species (Fl. 
Brit.) ; these he increases in his Compendium to twenty ; 
but Drs Hooker and Taylor, in their Muscologia Britan- 
nica, reduces them to fourteen. 
There are a few plants which require to be noticed in 
this place, some of which have been denied to belong to 
this genus, and others improperly retained. 
(Edipodium, the new genus constituted by Schw.e- 
GRTCHEN, we have already mentioned. Gymnostomum 
trichodes has been described by Hedwig as an Jnictan- 
gium, by Smith as a Grimmia, and as a Weissia by 
Drs Hooker and Taylor. We are more inclined to 
follow Weber and Mohr, and other authors, who deny 
it a peristome, than those who hold a contrary opinion. 
The authors of the Muscologia Britannica observe,— 
" The curious peristome of this plant, in an early stage, 
represents only a membranous ring, lying horizontally 
within the edge of the mouth of the capsule : this, however, 
as maturity advances, splits into sixteen equal, short, and 
very obtuse teeth, which become erect, and afterwards re- 
flexed over the mouth of the capsule." Sir J. E. Smith, 
in Eng. Bot. tab. 2563, also remarks, " Mr Borrer ob- 
serves, that the fringe seems a continuation of the inner 
coat of the capsule, and looks at first like a thin inflexed 
membrane, nearly closing the mouth; afterwards, when 
dry, it becomes refiexed, forming sixteen very short, blunt, 
flat, and pale teeth, and soon falls off.— -Mr J. D. Sowerby 
found each tooth divided by a line, transversely furrowed, 
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