TORTULACEAE 41 



Leaves with a lighter margin as in some species of Fissidens. 



Desmatodon Porteri 



12 — Costa excurrent Pottia 



Costa ending below apex Hyophila 



PHASCUM (L.) Schreb. 



Is a genus clearly intermediate between the Ephemeraceae 

 and the Tortulaceae, but more closely allied to the latter. Plants 

 very small, growing close together, with short erect stem clearly 

 marked, thus differentiating the genus from most of the Ephemer- 

 aceae. Leaves ovate to lanceolate and entire (in our species), 

 papillose above. Capsule immersed or somewhat emergent, 

 subglobose. 



P. cuspidatum Schreb. Closter, Austin; Highbridge, N. Y.; 

 New Dorp, S. Id., E. G. B., all at Bx! Also Muse. App. 53 

 from N. J. Early spring. 



Subfamily Weisieae 



Small persistent plants with stems usually short and rarely 

 radiculose, not glossy. Leaves lanceolate or linear-lanceolate, 

 equally spreading, usually keeled, seldom obtuse, twisted when 

 dry, basal leaf cells hyaline and rectangular, upper almost 

 always isodiametric and papillose; costa usually strong. Cap- 

 sules mostly exserted (except in Astomum), small, symmetric,' 

 oblong or ovoid, seldom cylindric, with stomata normally 

 phaneropore, capsules cleistocarpous (in Astomum), gymnos- 

 tomous, or peristomate. Peristome when present of 16 short, 

 more or less imperfect, entire or somewhat divided, erect teeth. 



ASTOMUM Hampe 



Small gregarious mosses growing on soil. Leaves crisped 

 when dry, narrow, keeled; upper leaf-cells small, round, quad- 

 rate, papillose on both sides. Capsules immersed (in our species) 

 subglobose, apiculate, oftentimes with a distinctly formed 

 lid which can be removed but which does not fall of itself: 

 calyptra cucullate. 



Easily distinguished from Bruchia by its deeply immersed 

 capsules, and from both Bruchia and Pleuridium by the leaves 



