THE GENUS HYMENOSTOMUM IN NORTH AMERICA. 
John M. Holzinger. 
Have we this genus in North America ? This depends somewhat on the 
point of view. I think we have here a moss which in Europe passes for a 
Hymenostomum. 
Hymenostomum R. Br. in Trans. Linn. Soc., 1819. The following is the 
historical view of this genus drawn up by Prof. Limpricht in Laubmoose, 
1, p. 223, 224: “ Hymenostoinum (membrane-mouth or-orifice), founded on 
Gymnostosmum microstomum Hedw. , is characterized by the author as a 
natural genus not merely by reason of characteristic external appear- 
ance but by reason of the structure of the capsule. The authors of 
Bryologia Germanica (1823) emphasize its affinity with Weisia viri- 
dula , and they include besides H. rutilans (Hedw.), also H. squctrrosum 
Bryol. Germ., H. obliquum N. v. E., H. brachycarpon Bryol. Germ., H. 
subglobosum Bryol. Germ., and H. crispatum Bryol. Germ.; however the 
last species is withdrawn again in 1831 by the authors in Bryol. Germ., if. 2. 
p. 33. Huebener in 1833 considers H. obliquum and H. brachycarpon as 
varieties, recognizes Phascum rostellatum Brid. as a Hy 7 nenostomum y 
designates it however as H. 7 nicrosto 7 num var. ( 3 . mutilatu 7 n Heuben. In 
Bry. Eur., 1846, Gy 77 inosto 77 tu 7 n tortile Schwaegr. is after Fuernroh’s example 
described as a Hy 77 / ienostomu 7 n, however H. rutilans (Hedw.) is made a 
synonym of Weisia 77 iucronulata Bruch., and H. subglobostwi Bryol. Germ, 
a synonym of Weisia 'viridula ; further H. rostellatum is treated as an 
Asto 77 iU 77 i, and by error H. crisp atimi Bryol. Germ, is also removed. C. 
Mueller in his Synopsis (1849) treated Hy?nenosto 77 tit 77 i as a subgenus of 
Weisia\ so also Juratzka (1882). Schimper in i860 puts it as a subgenus, 
under Gy 7 miosto 77 ium, yet G. rostellatu 7 n is counted in; in the second edition 
of the Synopsis (1876) it is again raised to the rank of a genus and H. un - 
guiculatum Phil, is added: by gross error H. crispatU 77 i Bryol. Germ, and 
H. 7 nurale (Spruce) are placed here. In Milde, who followed Lindberg, the 
genus is withdrawn in 1869, and its species are thrown in the subgenus 
Euweisia C. Muell, emend. Lindberg, in 1879. considered Hymenosto 7 num , 
including Euweisia C. Muell. and Asto 77 iU 77 t (Systegiinn.) as a subgenus of 
Mollia Schrank emend., a genus which in respect to structure of capsule and 
the anatomy of its stem and of leaf costa comprises in its limits diverse ele- 
ments. Since according to present views a valid taxonomic arrangement 
cannot be founded on the structure of vegetative organs merely, Hyiiienosta- 
mu 77 i is entitled to generic rank, for here in the so-called hymenium of the 
spore case we find a structure which has its analogue only in the “drum- » 
head,” (the epiphragm or diaphragm) of the Polytrichacese. Strictly speak- 
ing H. 77 iicrostomum and H. squarrosu 7 n are the only representatives 
within our territory, for H. rostellatu 77 i may be viewed as an Asto 7 nu 7 n and 
H. tortile probably does not belong here at all. That H unguiculatu 7 n 
Phil, represents a Trichosto 7 nu 77 i 77 iutabile with rudimentary peristome is 
known; yet Hy 77 ienosto 77 iu 77 i Mue l leri Bruch from Corsica (Flora, 1829, t. 2 
