— 8o— 
PTYCH0MITR1UM LEIBERQII n. sp 
G. N. Best. 
In loose tufts, olive green above, ferruginous below: stems i cm. long, 
erect, central strand small, distinct: leaves thickish, crispate-incurved when 
dry, erect-spreading when moist, somewhat undulate, entire, margins plane, 
3.5 to 5 mm. long, .6 to .8 mm. wide: from a concave, suboval base gradually 
linear-lanceolate, acute or blunt pointed: nerve thick, reddish, disappearing 
at apex ; lamina mostly unistratose, bistratose in streaks above and on the 
margins; leaf cells uniform, somewhat distinct, median chlorophyllose, 
roundish-quadrate, 10/z, basal broadly rectangular, pellucid: monoicous: 
antheridial buds at base of pedicels, stipitate; perichetial leaves similar to 
but larger than stem leaves: pedicels reddish, 5 mm. long ; capsules erect, 
elliptical, 1.3 mm. long. .7 mm. wide, wrinkled when dry; annulus broad, 
3 rowed, separating readily and in fragments: exothecal cells thin-walled, 
polymorphous, 3 to 5 rows about the mouth thick-walled, reddish, flattened; 
peristome simple, teeth narrowly linear-lanceolate from a broader articu- 
late base, yellowish, coarsely papillose, more or less irregularly divided, 
sometimes nearly entire; operculum acicular, .1 mm. long, zigzag on margin; 
calyptra campanulate, deeply lobed, plicate, rough at apex: spores minutely 
roughened, 13 to 16 ju: matures in the early part of February: on rocks, 
collected by John F. Lieberg, in whose honor it is named, near the south 
end of Baboquivara range, Arizona, February, 1906 : altitude 4000 ft. 
Cotype in the Herbarium of the New York Botanical Garden. 
Ptychomitriicm Leibergii differs from P. Gardneri by its smaller size, 
entire leaves, somewhat undulate but not plicate, and by its peristomial teeth 
not divided to the base into filiform segments. The leaves in P. incurvum 
are bistratose above the middle, leaf cells smaller and less distinct and the 
peristomial teeth entire.* 
In P. Druimnondii the leaves are denticulate-serrate, the peristomial 
teeth shorter and broader and split at apex and the annulus wanting. The 
leaves in the Mexican P. rugosum (Mitt.) Jaeg. are serrate above and re- 
flexed below. 
It would therefore seem that so far as the North American species of 
Ptychomitrium go P. Leibergii is well marked and quite distinct. Unfortu- 
nately it is described from a single collection. Future collections may show 
variations not recognized in this description. Mr, Leiberg assures me that 
it is “common in the mountains of southern New Mexico and Arizona from 
the Floridas in the former territory to the Baboquivara range in the latter, 
and probably extending much farther westward : southward into Mexico . 
not observed north of Southern Pacific R. R.” I am indebted to Mrs. Brit- 
ton for an examination of this moss and for the opinion that it is an unde- 
scribed species. Rosemont, New Jersey. 
*Mrs. Britton claims that P.pygmceum is only P. incurvum (Bull. Tor. Bot. Club, 21:497}. 
However this may be I am of the opinion that we have two species passing as P. incurvum 
differing in size, basal cells and peristomial teeth, possibly connected by intergrading 
forms. 
