1910] RIDDLE—STEREOCAULON 303 
g. STEREOCAULON ALBICANS Th. Fr. 
S. albicans Th. Fr. Comm. Ster. p. 36. 1857. 
S. tenellum Tuck. Bot. Wilkes Voy. p. 123. 1861 (according to type speci- 
mens). 
Podetia short, mostly under 1 cm., slender, caespitose, branched, 
crowded and intertangled; squamules minutely granular, becom- 
ing powdery; apothecia unknown.--The whole plant is character- 
istically chalky-white and powdery. 
SPECIMENS EXAMINED 
Nortu America: Greenland, Kikkeston Is., Howgate Exped. 1877 (Tuck); 
Vancouver Is., Macoun May 10, 1893 (Can); Colorado, T. S. Brandegee 
(BSNH); Astana. Rincon Mts. near Tucson, J. C. Blumer Oct. 1909 (R); 
California, C. R. Orcutt (BSNH); W.G. Farlow (H); Guadeloupe Is., Bi Fame 
1875 (Tuck): Cuba, C. Wright (Tuck). 
America: New Granada, Lindig no. 2502 (Tuck); Peru, Wilkes 
Exped. (Tuck), type of S. tenellum Tuck. 
This is a rare and interesting species, first described by Tu. Fries from 
material collected by GaupicHaup in Peru, but with a wide distribution as — 
indicated. It is the representative in the western hemisphere of the Old World 
S. nanum Ach. It does not resemble any other American species sufficiently 
to cause confusion. 
DOUBTFUL SPECIES 
Stereocaulon nanodes Tuck. in Suppl. II to Enum. N. A. Lichens, 
Am. Jour. Sci. 28:201. 1850. 
Primary thallus absent; podetia about 1 cm. tall, dendroid- 
branched, glabrous, more or less denuded; squamules in the form 
of small rounded granules, dissolving into fine, whitish powder 
(but not chalky as in S. nanum); apothecia terminal, or absent 
and the podetia ending in masses of soredia as S. pileatum.—Spores 
24-42X 2.5-3 M. 
I have examined at the Tuckerman Herbarium the type specimens of this 
Species, collected by TucKERMAN at Crystal Falls, Saco Falls, and upper gorge 
of the Ammonoosuck, in the White Mts., New Hampshire. Although not 
readily referable to any other species of Sivencuilan I have placed this species 
as doubtful on account of the fact that it has apparently never been collected 
again in the White Mts., which is perhaps one of the most thoroughly explored 
Tegions, botanically, in North America. The only other record of this species 
is Newfoundland on the authority of Dr. J. W. Eckreupt. Through the 
Courtesy of Mr. Witmer STone of the Philadelphia lwresteg ha? of Sciences I 
