Mr. Brown on Lyellia, Leptostomum, and Buxbaumia. 561 



in the early stage at least, connected by numerous plicae with 

 those elevations of the surface of the columella, which are no- 

 ticed in my description, and well expressed in Mr. Bauer's excel- 

 lent figure. 



My principal object, in the present paper is to establish 

 another genus of the same family, equally related to Pohjtrichum 

 in habit, which resembles Dawsonia in the remarkable form of 

 its capsule, but whose peristomium is of so peculiar a structure 

 as to require its separation from both these, and readily to di- 

 stinguish 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 particularly studied, 

 and made several important discoveries in, the natural order to 

 which it belongs. 



Mr. Hooker has already intimated his intention of establishing 

 a Lyellia in the same order, to consist of those species of Leuco- 

 don that have a mitriform calyptra*; 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 accom- 

 pany the present communication, I trust he will give the necessary 

 illustration of this interesting genus, in an early number of his 

 excellent Musci Exatici. 



LYELLIA. 



Stoma edentulum, clausum epiphragmate (crasso depresso), cujus 

 discus circularis a limbo (latiori) persistenti sccedens, cum colu- 

 mellci remanenti inclusA cohaeret. 



Capsula hinc plana inde convexa. 



Calyptra cucuUata (apice pilosa). 



• Musci Exotici, vol. i. 17. 



Mvscus 



