BULLETIN 
TORREY BOTANICAL CLUB. 
Contributions to American Bryology.—VIl. 
By E.izaseTu G. Britton. 
A REVISION OF THE GENUS PHYSCOMITRIUM, WITH 
DESCRIPTIONS OF FIVE NEW SPECIES. 
(PLATES 197-203.) 
When Sullivant’s Mosses of the United States was published in 
1856 he recognized three species in this genus, two with European 
names, one of which has since been referred to Pyramidula; the — 
third, P. ¢mmersum, having gone through the transitional stage of — 
aring a European name which ‘did not belong to it, by being 
stributed as P. sphericum in Sullivant’s Musci Alleghanienses. _ z 
We think as much harm may be done, however, by referring = 
- Well-known species to old disused names as by adopting Euro- 
Pean names without comparing specimens, and therefore it has 
“en attempted in this contribution to see the originals in all cases. — 
The Manual of mosses of North America describes six species. 
e€ first, P.immersum Sull., is clearly defined and understood. 
« Second, P. pygmeum James, has only been collected once, is_ 
Poorly described, and the only fragments of it preserved in Sulli- — 
f -°Mts herbarium are a slide and a drawing. The third, P. pyr — 
_ Sorme (L.) Brid., is a European species, the typical form of which ‘ 
does not occur in America. In a footnote several American varie- — 
Nes are briefly described. The fourth, P. Hookeri Hpe., is correctly 
Understood, and the name has the right of priority, but she Dest 
ag nonym given belongs to the last species. _ The fifth, P. acumin- 
di 
