318 | Mr. Brown’s Observations on. the 
merosissimis (200 et ultra) capillaribus inarticulatis zequalibus 
rectis albis opacis, pluribus e capsule parietibus ortum du- 
|. centibus, centralibus (circiter 50) columellam terminantibus ! 
Membrana interior capsule maturæ exteriori approximata, vas- 
P . culisque numerosi$ connexa. 
M sella longitudine capsule matura, in qua latiuscula, cor- 
rugata, colli brevis margine incrassatä, intra cilias desinens in 
processum filiformem solidum indivisum apicem operculi at- 
tingentem eique arctius adhzrentem. 
Semina minutissima, levia, in cumulo viridia, seorsum hyalina. 
Oss. I. I have named this remarkable genus in honour of my 
esteemed friend Dawson Turner, Esq., a gentleman emi- 
. pently distinguished in every part of Cryptogamic botany, and 
from whom, after he has finished the incomparable work on 
Fuci, in which he is now engaged, we may expect a general 
history of Mosses. 
Obs. 11. The strict relationship between Dawsonia and Polytri- 
^. chum in most respects, and the striking dissimilarity of their . 
peristomiums, 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. "Ihe*better to understand that of Polytrichum, I was 
induced along with Mr. Turner to examine it in the unripe 
-eapsule: 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 
