OF ARTS AND SCIENCES. 139 



basi obsolete bicostata ; reticulum pertenue areolis perangustatis bre- 

 viter vermiculatis in toto folio suba^qualibus. 



Flores dioici; perichretium in ramulo perichoetiali perbrevi haud 

 radicante longum vaginans ; folia perichastialia interna elongato-lan- 

 ceolata, subulato-acuminata, apice denticulata, tenuissima, pallida, 

 longitudinaliter plicata, plicis angustis, reticulo laxiore tenuissimo. 



Capsula leniter cernua, elongato-subcylindrica, sicca arcuata sub ore 

 leniter constricta ; operculum oblique rostratum, rostro mutico. 



Color totius plantae lutescens et fuscescens. Habitus et modus 

 crescendi H. Bambergeri. 



Hypnum imponens, James in Bot. King Exp. 410. 



Hab. On rocks, Bear River Canon, Uinta Mountains, Utab ( Watson, 

 no. 1474). 



Tbis species is comparable at first sigbt to some of tbe varieties of 

 H. uncinatum, but is different from this and related congeners in its 

 inflorescence, form, areolation of leaves, &c. 



Hypnum Alaskanum. Differt ab H. Schreberi proximo gracilitate 

 plantos densius et regulariter pinnate ; foliis caulinis minoribus solidi- 

 oribus, apice minus late rotundatis, margine remote serratis ; reticulo 

 validiore, areolis totius folii vermicularibus et prreprimis superioribus 

 angustioribus et brevioribus ; prsesentia paraphylliis multifidis. 



Hab. On tbe ground in Alaska ( W. H. Dall). 



Distinguished from H. Schreberi by its densely pinnated form ex- 

 tending the whole length of the stem, also by its broader and slightly 

 serrated leaves and dark color. 



The following descriptions, with remarks on some new American 

 species, have been communicated by Professor Schimper : — 



Ephemerum spinulosum, Schimp. Differt a E. crassinervio, foliis 

 angustioribus mollissimis versus basin ecostatis, parte superiore costa 

 instructis lata laxe texta in aristam longam mollem circa circum 

 hyalino-spinulosam excurrente ; capsular membrana laxius texta. 



Hab. Moist clayey grounds and on river-banks. 



Schwaegrichen's Phascum crassinervium is a Pennsylvania moss, 

 and the same as Ephemerum crassinervium of Sullivant's Icones, but 

 not identical with E. crassinervium, Bryol. Eur., which is Phascum 

 stenophyllum, Voit (E. stenophyllum, Schimper, Synopsis, second 

 edition). [There is great difficulty in separating these forms, which 

 are often found together, and so closely allied by intermediate vari- 

 ation that it is scarcely possible to decide which of these species is 

 represented by the specimens. Considering merely the variations in 



