l8 9 r -] Notes on American Mosses. 



205 



Plate XX.— Everhartialigmtilis, n. sp. Fig. 10. General habit showing 

 rounded mass of extruded spores, XG8. Fig. 11. Sterile and fertile hyphae of 

 sporodochium, showing stages in formation of helicospores, XMY\. Fig. 12. 

 Mature spores, X606. 



Plate XX.— Everhartia hymenidoides Sacc. & Ell. Fig. 13. Mature spores, 

 X696. Fig. 14. Spore in situ, showing terminal formation, X696. 



Notes on North American Mosses. II. 



CHARLES REII) BARXES. 



DlCRANUM PALUSTRE LaPyl.— This species has not been 

 noted as particularly variable as is the case with its congener, 

 D. scoparium Hedw. The examination of a large series of 

 specimens, collected in various parts of the northwestern 

 United States by Dr. Julius Roll in 1888, has shown me that 

 it is almost as polymorphous as D. scoparium, and that 

 it ^ intergrades so closely with that species that it is 

 quite impossible to limit it except in a wholly arbitrary 

 way. The var. paludosum of D. scoparium imitates some- 

 what the typical D. palustre in the rugulose and shorter 

 pointed leaves. But this is a character by no means constant 

 in the- latter species. Indeed it is oftener absent than pres- 

 ent. There is also no reliable distinction to be drawn from 

 the section of the costa. We have therefore simply to say 

 that those forms with slender pointed often falcate leaves, 

 having the cells somewhat elongated in the upper part, shall 

 be grouped with D. scoparium. I have not thought it worth 

 while to characterize separately any of those forms of D. pa- 

 lustre (among which the Californian variety Brewerianum of 



I^esquereux may well be placed) which connect with the pa- 

 lustral modifications of D. scoparium. If one should begin, the 

 list might rival that of some of the Sphagna! On the other 

 hand D. palustre shows numerous variations toward forms 

 with broad leaves, entire or coarsely serrated and usually not 



wrinkled. Three of these I have separated as well-marked 

 varieties, 1 which fall more or less closely into company with 

 the Kuropean vars. juni peri folium and polycladon of the Bry. 

 Eu. Had the intermediate forms been lacking from the col- 

 lection I should have unhesitatingly established these, or at 

 least the var. Rocllii, as species. 



Having already examined a considerable number of the 

 species of Dicranum in determining the Weisiace.e of Roll's 



1 Botanisches Centralblatt xliv. 380 (181)0). 



