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base, not clasping, shortly decurrent at the basal angles, cari- 
nate above and reflexed on the margins, strongly costate, the 
nerve pluri-stratose, more or less channeled, above becoming 
laminoid and gradually narrowing into a long straight or flex- 
uous hair with a few weak salient or appressed teeth; cells of 
the areolation elongated-rectangular below, broader, sub- 
graduate in the middle, small-graduate above, chlorophyllose, 
all sinuous and the cell walls very thick and dense and re- 
markably elastic; the margin of the leaf of two or three rows 
of nearly graduate cells, and the extreme base and decurrent 
angles of a few irregular, oblong or subrhombic, ones. Inflor- 
escence dioicous; ¢ plants growing mixed with the 9 usually 
somewhat shorter and more branched, occurring but sparingly ; 
antheridial buds in the axils of the innovations, occasionally 
terminal on very short lateral branchlets, perigonial bracts 3-4, 
short, acute, thinly costate; cells of the upper half of the bract, 
narrow, short-rectangular or quadrate, sinuous, chlorophyllose, 
of the lower half broad-rectangular, straight, hyaline; anther- 
idia large, numerous without paraphyses; archegonial inflor- 
escence from secondary branches, sometimes direct from the 
axils of the innovations. 
Capsule oval or oblong 2-5 mm. long, often two from the same 
perichetium, pendent on a twisted pedicel, 0.5—1 cm. in length, red 
and narrowed at the mouth, with a distinct collum, substrumose, 
at least when fresh and mature, erect when dry and pedicel more 
strongly twisted, longitudinally wrinkled, the ridges prominent, 
continuous or interrupted, 4-8 in number; perichetial leaves only 
sheathing to a little above the vaginule, otherwise similar to the 
stem leaves; lid red, subulate, 44-3 of the length of the capsule. 
Calyptra 4-5 lobed covering the lid only. 
Teeth of peristome cleft to below the middle into two seg- 
ments, sometimes merely lacunose along the median line, thin, 
minutely papillose above the middle when fresh, articulations few, 
incurved when dry. Annulus simple, of two rows of thin cells, 
narrow, strongly persistent, detaching in fragments. 
Habitat granite, gneissoid and slate rocks throughout Kootenai 
Co., Idaho. J. B. Leiberg, No. 250, 1890-92. Characterized 
from living specimens. 
A fine form of the Rhabdogrimmia section, most nearly related 
to Grimmia decipiens (Schultz), Lind., from which species it differs 
mainly in its dioicous inflorescence, its open leaf base, smoother 
hairy point, its broader basilar, its shorter medial, and its quadrate- 
