574 JIfr. BiiowN on Lyellla, Lcptoslomum, and Buxbaiuma. 



ing the columella in several species of Splachnitm ; and perhaps 

 even the tj'mpanum of Poli/tricJtnm may be of similar origin. 



But these characters of Leptostomuiu and Hijmaiosiomitm, though 

 they do not appear to have been yet observed in any other mosses, 

 may still perhaps be considered too aiinute for generic distinc- 

 tions: and it must be admitted that were nothing to be obtained 

 but the subdivision of an extensive natural genus it could not be 

 necessary to have recourse to them. The divisions in question, 

 however, are certainly not of that kind. 



The weakest part indeed of Hedwig's system is its bringing to- 

 gether all those mosses that have a naked peristomium, and even 

 including the greater partof them in the genus G?//nnos;ow«7«; while 

 many of the species so associated are in real affinity much nearer 

 to several other genera of the order having a simple or even a 

 double peristomium. 



Thus Gymjiosiomum microsiomiim, the Hymenosiomum of the pre- 

 sent paper, has less the habit of the genus in which it is placed than 

 of TVeissia, to some of whose species, especially JV.affinis and tricho- 

 (les, it seems to approach even in the structure of its peristomium. 



Several species of that section of Gi/mnostomiim, to which per- 

 haps the genus should be limited, especially G. fascicular e, Bon- 

 plandii, and Rotileri, can hardly be distinguished from JVeissia 

 Templet oni*. 



• JJlissia Templetum, along with a nearly related species found in New Holland, Fu- 

 nnria minor of Delile {Flor. JEgypt.), and perhaps also Weissia radians, \n3.y faxm a genus 

 distinct from IVeissia, and nearly related to Funaria, differing chiefly in the irregular burst- 

 'w and evanescence of the inner peristomium, which in Funaria is regularly divided and ge- 

 nerally persistent, though in some cases perhaps equally deciduous. In a variety of lliissia 

 Templetoni, or a very nearly related species, collected in 1800 in the county of Donegal, 

 \ have observed the outer peiistomiuui to be not unfrequently wanting, even before the se- 

 naratioji of the operculum ; a fact which, if hereafter coafirmcil, would establish its affinity 

 to Gymnoitomtim fusciculare. 



Gymnosiomuni 



