318 Mr. Brown's Observations on the 



nierosissimis (200 et ultra) capillaribus inarticulatis aequalibus 

 lectis albis opacis, pUiribus e capsulse parietibus ortum du- 

 centibus, centralibus (circiter 50) columellain terininantibus ! 



Membrana interior capsulae tnaturte exteriori approximata, vas- 

 culisque numerosis connexa. 



Columella longitudine capsular maturas, in qiiA latiuscula, cor- 

 viigata, colli brevis margine incrassatii, intra cilias desinens in 

 processum filifornieui solidum indivisum apiceni operculi at- 

 tingentem eique arctii^is adhaerentem. 



Semina minutissima, lajvia, in curaulo viridia, seorsilm hjalina. 



Obs. 1. I have named this remarkable genus in honour of my 

 esteemed friend Dawson Tuunkk, Esq., a gentleman emi- 

 nently distinguished in every part of Cryptogamic botany, and 

 from whom, after he has finished the incomparable work on 

 Ftici, in which he is now engaged, we may expect a general 

 history of Mosses. 



Obs. II. The strict relationship between Darcsonia and Poli/tri- 

 chum in most respects, and the striking dissimilarity of their 

 pcristomiums, may tend, perhaps, in some degree to lessen our 

 confidence in the characters derived from that part ; for there 

 seems in this case but little analogy between the two struc- 

 tures. The better to understand that of Folytrichum, I was 

 induced along with Mr. Turner to examine it in the unripe 

 capsule: in this state the cavity of the operculum was 

 found completely filled with a cellular pulp, similar to that 

 composing the columella, of which it appeared evidently to be 

 a continuation : to the surface of this pulp the teeth of the pe- 

 ristomium were closely pressed, but did not adhere : by degrees 

 the pulp dries up, and in the ripe capsule leaves only the 

 membrane or tympanum of an inorganic appearance, and 



firmly 



