— 6 — 
7- Rhacomitrium macounii Kindb. Bull. Torr. Bot. Club 16: 93. 1889. 
[R. alternatum C. M. & Kindb.; R. robustifolium Kindb.] 
Plants green to brownish or blackish. Stems up to 7 cm. long; elongated 
branches few or none, short tuft-like lateral branches none or occasional. Leaves 
ovate-lanceolate; when dry loose, crispate, nearly erect; when moist recurved; 
apex obtuse to acuminate; hyaline tip none, or short and smooth; margin of 
opaque portion entire, 2 cells thick toward the apex, erect on one side, erect 
or revolute on the other; costa extending to the apex or nearly so. Cells some- 
what sunken over the lumen; those near the leaf-tip isodiametric; those of the 
leaf-middle a little longer than wide; those of the leaf-base linear, sinuose; lower 
marginal row quadrate to rectangular, some of them hyaline. Seta twisted 
to the right, about 5 mm. long, smooth, straight, or nearly erect and contorted. 
Capsule oblong, dark brown, not striate; its body about 1.8 mm. long. Per- 
istome-teeth orange to brown, perforate or cleft to below the middle, smooth, 
about .26 mm. long.— British Columbia to Oregon. 
An examination of co-type material kindly lent by Professor J. M. Macoun 
shows that the leaf-margins are two cells thick near the tip instead of 1 cell thick 
throughout as described by Kindberg. Also the leaves are hardly smooth; 
the surface is quite sunken over the cell cavities. The larger plants usually 
show fewer recurved leaves when dry, and constitute what is known as R. robust- 
ifolium. But the leaf and capsule characteristics agree very closely. Here 
is referred Macoun’s number 245 from Mt. Arrowsmith, Vancouver Island, and 
distributed as R. robustifolium. 
8. Rhacomitrium affine (Schleich.) Lindb. Acta Soc. Sci. Fenn. 10: 552. 
1875. [R. alopecurum Brid.; R. heterostichum alopecurum Huebn.; R. obtusum 
Brid.; R. affine obtusum Limpr.; R. heterostichum gracilescens B. S. G. ; Grimmia 
obtusum Lindb.] 
Plants green to yellowish brown. Stems up to 5 cm. long; elongated branches 
few, short tuft-like lateral branches many. Leaves lanceolate, nearly smooth, 
recurved when moist; apex obtuse to acuminate, muticous to hyaline-pointed; 
margin denticulate along hyaline point, otherwise entire, 2 cells thick toward 
tip. Cells of leaf-tip mostly isodiametric although some longer, of the leaf- 
middle rectangular, of the leaf-base linear; alar cells few, small, isodiametric; 
vein disappearing somewhat below the apex. Dioicous. Calyptra somewhat 
rough on the beak. Seta 4-6 mm. long, twisted to the right. Capsule 1.7-2. 4 
mm. long, cylindric; lid } ■/&—-}£ the length of the capsule-body; annulus of 2-3 
rows of cells. Peristome-teeth .25~.32 mm. long, densely papillose, divided to 
below the middle into 2 divisions. — Alaska to Washington. 
The lack of hair points on some plants does not seem to warrant a variety. 
The gradation is close. It is very likely that the amount of hyaline tip depends 
upon the conditions under which the plant is growing; apparently drought favors 
more and longer hyaline tips. 
Here are referred Macoun’s number 98 from Unalaska, Alaska, and his 
number 622a from Nova Scotia. 
