332 ON LYELLTA, LEPTOSTOMUM,
surface of the columella, which are noticed in my description, and well expressed in Mr. Bauer's excellent figure.
My principal object, in the present paper, is to establish another genus of the same family, equally related to Poly- trichum in habit, which resembles Bawsonia in the remark- able form of its capsule, but whose peristomium is of so peculiar a structure as to require its separation from both these, and readily to distinguish it from all other genera of Mosses.
This new genus I shall name Lyellia, in honour of Mr. Charles Lyell, an accurate English Botanist, who has par- ticularly studied, and made several important discoveries in, the natural order to which it belongs.
Mr. Hooker has already intimated his intention of estab- lishing a Lyellia in the same order, to consist of three species of Leucodon that have a mitriform calyptra ; 1 but he has readily agreed to transfer the name of our friend from a genus, respecting which there is still some uncertainty, to one so unquestionable as that here proposed ; and as I have not a drawing prepared to accompany the present com- munication, I trust he will give the necessary illustration of this interesting genus, in an early number of his excellent Musci Eccotici.
LYELLIA.
Stoma edentulum, clausum epiphragmate (crasso depresso), cujus discus circularis a limbo (latiori) persistenti secedens, cum columella remanenti inclusa cohseret.
Capsula hinc plana inde convexa.
Calyptra cucullata (apice pilosa). 562] Muscus (Nepalensis) habitu Polytrichi; capsula* figurd et structurd interiori Dawsoniae similis ; peristomio ad utroque genere diversissimus.
1 Musci Exotici, vol. i. 17.
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