POTTIACEAE. lll 
e only species with which it is likely to be confused is the gymnos- 
tomous form of Weisia viridula. That, however, is readily a by 
the longer, very dag seta, the capsule more bri rightly coloured when ripe 
the mouth not closed by a membrane, the beak “of the 
lid more slender ste less cae decurved, the leaves narrower and mo 
delicate, the ie ae ones usually considerably longer than the ordinary 
leaves, while in H. patulum they are usually about equal, or shorter. 
A. eich. is marked by the dull colour of the capsule, on a quite short 
seta, the mouth closed, at the fall of the lid, by a membrane—this being 
the principal generic character—the lid with a long, stout beak, usually as 
long as or longer than the capsule, and bent downwards at right angles or 
even decurved. In this, as well as in the leaf-margin only incurved above, 
not enrolled, and in the weaker, less reddish nerve, it differs from the 
H. tortile of erode and is, indeed, perhaps more nearly allied to 
H. microstom 
ave seen no specimen of Gymnostomum patulum prt but there 
can be no doubt from the description and figures that is describing 
the plant referred by Hooker and Wilson to G. tortile it appears to be 
ac on species in New Zealand. I have sara the specimens in 
have no doubt that they may all be refered pee to this austral 
species (e.g., “H. 306, N.Z.— % Hymenostomum patens Wils. MS.” 
* Col. 364”; and “ Col. 215 p.p.’), or in 18 case of others to the plant 
described below as Wersia viridula var. gymnostoma (Hook. 305, : 
Trichostomum subuliferum Mitt. MS. in herb. (N.Z., Travers, " 1860) 
also belongs here, as does Hymenostomum neglectum Hampe MS. in herb. 
R. Brown ter., in some pertinent notes on Knight's species of 
Gymnostomum (Trans. N.Z. Inst., vol. 26, p. 297), calls attention to the 
fact that Wilson had already proposed the name G. patulum for the 
gymnostomous form of Weisia viridula, and that Knight does not make 
it clear whether it is this particular moss or another species which he 
describes as G. patulum. It is, I think, certain that Knight did not 
the choice of name is certainly unfortunate. Brown 
would be much more descriptive; but Wilson’s G. patulum cannot be 
held to be gers published, not being accompanied by a description, 
and Knight’s name must therefore stand. 
The leaves are usually decidedly broader than in W. viridula; the 
apex varies greatly in degree of acuteness, and the nerve in the extent 
of its excurrence; the margins may be quite plane, but, as a rule, the 
leaves are more or less concave above with the margins erect, and the 
uppermost may often have them distinctly and rather widely ‘ineurved, 
so that the apex becomes subcucullate. The areolation is dense and 
obscure, while the nerve, near the apex at least, is much more translucent. 
Wets1a Hedw. 
A genus difficult of definition, passing almost rani co Trichos- 
tomum on one side, and on the other into Hymenostomum. m the latter 
it differs in the capsule peristomate, or, if gymnostomous, sie having the 
mouth closed by an epiphragm ; from Didymodon and Trichostomum prin- 
papillose. The leaf-margin is usually erect or incurved, rarely recurve 
