DICRANACEAE 2$ 



Key to Genera 



i — Leaves glossy, not glaucous 2 



Leaves glaucous, with a waxy bloom Saelania 



2 — Upper leaf cells more or less elongated; capsules usually erect and 



smooth but sometimes inclined and somewhat wrinkled. . .Ditrichum 

 Upper leaf cells roundish-quadrate, sometimes slightly papillose; 

 capsules inclined and deeply furrowed when dry Ceratodon 



DITRICHUM Timm. 



Plants tufted, slender, growing on soil or rocks; upper leaf- 

 cells narrowly rectangular to quadrate; capsule on a slender 

 straight seta, oval to cylindric, erect or slightly inclined, with 

 an annulus; peristome erect, of sixteen long teeth, cleft into two 

 filiform papillose divisions, which are sometimes more or less 

 united. 



1 — Monoicous; seta yellow; costa long excurrent pallidum 



Dioicous; seta orange, red or brownish; costa short excurrent 2 



2 — Leaves secund, subulate; perichaetium not sheathing pusillum 



Leaves erect appressed, lanceolate; perichaetium sheathing lineare 



D. pusillum (Hedw.) Timm. [D. tortile (Schrad.) Hampe.] 

 Very common on bare, rather moist soil. Autumn-spring. 



D. lineare (Sw.) Lindb. [D. tortile vaginans (Sulliv.) Grout.] 

 With the same habitat as the last but less common. Autumn. 

 Immature sporophyte (in early August) is sometimes bright 

 yellow. 



D. pallidum (Schreb.) Hampe. Common in rather dry 

 sandy places. June. 



SAELANIA Lindb. 



Leaves linear-lanceolate, serrate, costate to apex. Differing 

 from Ditrichum chiefly in the granular or filamentous '"bloom" 

 on the dorsal surface of the leaves, and the minute quadrate to 

 somewhat oblong leaf cells. 



S. glaucescens (Hedw.) Broth. "Crevices of rocks, Little 

 Falls, N. J., and Haverstraw, N. Y.," Muse. App. 121. 



CERATODON Brid. (Plate II, Fig. 2.) 



Plants short (sometimes reaching two or three inches in damp 

 shaded places) ; in dense cushions matted together with radi- 



