62 
Contributions to American Bryology—IX. 
By ELIZABETH G. BRITTON. 
(PLATES 229-231.) 
I. THe SysTEMATIC POSITION OF PHYSCOMITRELLA PATENS. 
It must have occurred to every student of the mosses of the 
United States that the foot-note* at the bottom of page 39 of 
Lesquereux and James’ Manual indicated a curious state of 
classification, and this feeling is increased when a study of the 
specimens and literature convinces him that the facts which have 
been taken for fixing arbitrary lines are still open to question and 
have been disputed by several well-known bryologists. The 
questions in doubt are these:—Has Physcomitrella patens a de- 
hiscent, differentiated, lid? and is it distinct generically from 
Aphanorhegma? We propose to answer both these questions in 
the affirmative. 
The history with regard to European specimens is best shown 
by the following citations :— 
PHYSCOMITRELLA PATENS (Hedw.) Br. & Sch. 
Phascum patens Hedw. Descr. 1: 28. pl. ro (1787). 
Physcomitrella patens Br. & Sch. Bryol. Eu. 1: p/. 3 (1849). 
Aphanorhegma patens Lindb. in Ofv. K. Vet. Akad. Forh. 580 
(1864). 
Limpricht (Rab. Kryptfl. 4: 174. 1886) and Braithwaite (Brit. 
Mosses, 2 : 127. 1890) maintain Physcomitrella as a genus and state 
that the capsule is indehiscent, or the lid not differentiated ; 
hence the former places it among the cleistocarpous mosses, and 
the latter, following Lindberg and Hampe, classes it with the 
Funariaceae. The latter is undoubtedly its most natural alliance. 
Lindberg claims to have seen the lid. Schimper in the last edition 
of the Synopsis Muscorum (1876) says that he has not seen it. 
“ De operculi vestigi a Clarissimo Lindberg laudato adhuc nil vidi.” 
*« Aphanorhegma serratum, Sulliv., differs from this spec.es (Physcomitrella 
patens) only in the regular dehiscence of the capsule, which divides in the middle and 
is therefore considered as operculate or stegocarpous, though no discoloration nor any 
kind of modification of the texture is observable on the line of disruption. But for 
this regular dehiscence Aphanorhegma should be described here merely as a variety 
_ _ of Physcomitrella patens. It is therefore a remarkable connecting link between the 
: Ephemereae : nd the Physcomitrieae, which resemble each other also in the areolation 
of the leaves.” 
