( 560 ) 



XXXV. Characters and Descriptio7i o/Lyellia, a new Genus of 

 Mosses, with Observations on the Section of the Order to which it 

 belongs; and some Remarks on Leptostomum and Buxbaumia. 

 By Robert Brown, Esq. F.R.S. Libr. L.S. 



Read April 6, 1819- 



In the tenth volume of the Society's Transactions, I have given 

 a description of Dawsonia, a genus of Mosses having entirely 

 the habit of Po/^/ric/u»?i, but whose peristomium, instead of con- 

 sisting of a single row of short teeth connected by a horizontal 

 membrane, is composed of an indefinite number of capillary cilia. 

 These cilia, originating both from the inner surface of the capsule, 

 immediately within the orifice, and from the columella itself, form 

 a loose pencil, of which the hairs are sufficiently distinct to allow 

 of a gradual discharge of the seeds. 



The correctness of this account of Dawsonia, especially as to 

 the origin of the peristomium*, and the nature of the supposed 

 columella-f , has been questioned by some of those authors, who 

 have since adopted the genus. 



From a careful re-examination, however, I find no reason to 

 alter in any respect the generic character formerly given ; and to 

 the description of the species I have only to add, that the upper 

 surface of the leaves is furnished with parallel lamellae, like those 

 of .Polytrichum ; and that the inner membrane of the capsule is, 



* Bridel Meth. Nov. Muscor. p. 205. 



t De la Pylaie in Journal de Bolanique appliq, iii. p. 134. 



in 



