THE BR YOLOGIST 
VoL. Xin May igio No. 3 
PLEUROCLADA ALBESCENS FOUND IN UNITED STATES 
OF AMERICA. 
Caroline Coventry Haynes. 
Innge 7 'niannia albescens Hook. Brit. Jung. pi. 72 and Suppl. pi. 4. 1816. 
Cephalozia albescens Dumort. Recueil. 18. 1835. 
Pleuroclada albescens Spruce. On Cephalozia, 78. 1882. 
This rare species was collected by Mr. C. V. Piper (95) on Mount Rainier, 
Washington, alt. 6500 ft. August, 1895. Herb. New York Botanical 
Garden. The writer detected it while studying the set of which it formed 
part, her determination being verified by Dr. Evans, who recently very 
kindly communicated part of a specimen collected by Mr. E. Jones, Sperry 
Glacier, Montana, alt. 7500 ft. August 29, 1909. Herb. A. W. Evans 
(10704). Both specimens show sterile plants. The species is distributed in 
the alpine regions of Northern Europe, and there are several stations for it 
in Greenland. The following description is derived from the works cited 
above and from Mr. W. H. Pearson. Hep. Brit. Is. 
Dioicous, growing in large, loosely matted patches, tufts depressed: 
plants, American, under 9 mm. in length; Sir William Hooker makes Euro- 
pean, from half to three-fourths of an inch in length; of a whitish green 
color, when dry with a bluish-white tinge; procumbent, loosely subpinnate, 
branching two or three times dichotomously ; slightly radiculose, rooting up 
to apex of stem; leaves somewhat distant, alternate, almost transversely 
inserted, slightly succubous, concave, almost hemisphaerical, bilobed one- 
third their length, segments ovate, triangular, connivent, sinus narrow or 
subobtuse; cells quadrate or hexagonal, smooth, pellucid, with delicate 
walls, no trigones; axillary leaf produced partly from the stem and partly 
from the adnate branch, differs from the other leaves in being broadly ovate, 
subcordate at base, apex acute, not bifid; underleaves subcontiguous, 
appressed, plane, slightly shorter than the leaves, broadly ovate to ovate- 
lanceolate, acute or subacuminate, rarely obtuse, on one side above the base 
deeply unidentate, sometimes unidentate on both sides or entire; perianth 
terminal on short or long branches, these radiculose at the base; bracts three 
pairs, appressed, convolute, the lower bracts a little larger than the leaves. 
The March Bryologist wa? issued March 9 , 1910 . 
