— 95 — 



body, usually diagonally beaked. Annulus of 3 rows of large cells. Peristome 

 teeth united at base, divided into 2-3 forks to well below the middle, purple, 

 densely papillose, .25-3 mm. long. Spores 12-16/i. — Alaska to Oregon, Idaho 

 and Montana. 



The separation of a poorly defined group under the generic name Dryptodon 

 seems to be more confusing than clarifying, and adds nothing to our knowledge 

 of relationships. It does not then seem to have sufficient reason for support. 



2. Rhacomitrium aciculare (L.) Brid. Mant. p. 80. 18 19. 



Plants rather coarse and stiff, green to blackish-green; stems up to 10 cm. 

 long; elongated branches few; short tuft-like lateral branches none. Leaves 

 broadly lanceolate or Ungulate; apex rounded, wide; margin usually somewhat 

 toothed at tip, only i cell thick throughout; vein ending a few cells from the 

 tip. Cells of the leaf-tip isodiametric or oval, of the leaf-middle rectangular, 

 of the leaf-base linear. Dioicous. Calyptra mitrate, smooth. Seta 3-14 mm. 

 long, twisted to the right. Capsule oval or almost cylindric, 2-2.4 long; 

 stomates in 3-4 rows; lid beaked, 3^-% the length of the capsule-body; annulus 

 of 3-4 rows of cells. Peristome about .7 mm. long, papillose; teeth divided to 

 below the middle into 2-3 unequal divisions. On wet rocks in or at the margins 

 of streams. 



The species varies chiefly as follows: (i) the margin of the leaves from 

 entire to distinctly toothed for ^ the distance to the base; (2) the cell arrange- 

 ment near the tip from fairly distinct diagonal rows to utter lack of diagonal 

 rows; (3) the length of seta from 3 to 14 mm.; (4) the vein in the inner peri- 

 chaetial leaves from %the distance from the base to wholly wanting; (5) the length 

 of the body of the capsule from 2 to 2.4 mm. The nearly ecostate perichaetial 

 leaves are usually but not always concurrent with the shorter setae and smaller 

 capsules; this constitutes R. nevii. But short and long setae sometimes occur 

 on the same plant. 



Typical. 



I. Seta 5-14 mm. long; capsule about 2.2-2.4 mm. long; inner perichaetial 

 leaves with vein indistinct to distinct. — Alaska and Yukon to California 

 and Montana. 



2a. Rhacomitrium ac'culare nevii (Muell.) n. comb. [Grimmia nevii Muell.; 

 Rhacomitrium nevii Wats.] 

 I. Seta 3-7 mm. long; capsule about 2-2.2 mm. long; inner perichaetial leaves 

 from ecostate to indistinctly costate. — Alaska to Oregon and Idaho. 



3. Rhacomitrium depressum Lesq. Mem. Calif. Acad. Sci. i: 14. 1868. 



Plants yellowish-brown to blackish-green. Stems up to 13 cm. long; elong- 

 ated branches none to few per plant; short tuft-like lateral branches none. Leaves, 

 obtuse, smooth; margin entire or with suggestions of distant teeth at apex, only 

 I cell thick throughout; vein ending a few cells from the tip. Cells of the leaf- 

 tip isodiametric or nearly so, those of the leaf-middle 2-4 times as long as wide 

 and sinuous, those of the leaf-base linear except for the lower few rows, Dioi- 

 cous. Calyptra (?). Seta 6-8 mm. long, twisted to the right. Capsule sub- 



