Parts of Fructification in Mosses. 323 
and it may perhaps in some degree tend to strengthen the 
character of Leptostomum, to advert to what appears to 
.be really the case in certain species of Pterogonium, in 
one of which * Mr. Hooker has already described the fringe 
as derived solely from the inner membrane; and I have 
collected, on the mountains of Van Diemen's Island, a- 
moss with a peristomium decidedly of like origin; a cir- 
cumstance that appeared to me so remarkable, that I had 
actually described it as a distinct genus, before I was aware 
of the similar structure of the Nepal plant described by 
Mr. Hooker; or of the probability, from’ Hedwig's own 
figures, that some at least of his Pterogonia were of the 
same structure; a point that I have not at present the means 
of determining, but which I beg leave to recommend to the 
attention of those botanists who are provided with perfect 
specimens of the published Pterogonia. 
EXPLICATIO TABULA XXIII. 
Pa 1. Dawsonia polytrichoides. a. Mascula planta magnitu- 
dine naturali. 6. Discus masc. auctus. c. Ejusdem flos 
unicus. d. Idem absque folio perigoniali, magisque auctus. 
e. Anthera et filum succulentum maxime aucta. f. Femineæ 
plante magn. nat. g. Vaginula cum foliis perichetialibus 
auctis. h. Capsula cum calyptra exteriori. 3. Pilicalyptre 
= exterioris magis aucti. j. Capsula cum operculo et calyptra 
. interiori. k. l. Capsula deoperculata cum peristomio. m. Cap- 
sul sectio ejusdem figuram insertionemque ciliarum os- - 
tendens. o. Calyptra interior. p. Operculum cum colu- 
* Pterogonium declinatum. Trans. Linn, Soc. ix. p. 309. 
i mellæ 
