1910] RIDDLE—STEREOCAULON 293 
Behring Strait, Trelease July 12, 1899, Harriman Exped. no. 1266, as S. tomen- 
tosum (CEC). 
AINE: Eastport, W. G. Farlow 1877 (Tuck); Portage, L. W. Riddle 
Aug. 1907 (R); Rangeley L. W. Riddle Aug. 1904 (R); Orono, L. W. Riddle 
July 1907 (R); Mt. Desert, M. L. Wilson (Mt. D), Sam Surrey (R); Rockport, 
G. K. Merrill Lich. Exs. no. 40; Cumberland, J. Blake (NY). 
New HampsuireE: White Mts., Tuckerman Lich. Exs. no. 122; North 
Woodstock, Clara E. Cummings in N. A. L. no. 25, L. B. A. no. 151; Can, 
Miss Minns (W); Warren, Charles W. Riddle Aug. 1908 (R); Mt. rege. 
H. H. Bartlett Sept. 1906 (R); Mt. Monadnock, W. G. ee pepe H. 
Howe, Jr. (Th); Fitzwilliam, R. H. Howe, Jr., Lich. Nov. Ang 
Vermont: Mt. Mansfield, C. G. Pringle 1879 (UVM); Willoughby, W. G. 
Farlow (H); Bristol, L. W. Riddle Aug. 12, 1908 (R). 
Massacuuserts: Pepperell, L. W. Riddle May 30, 1909 (R); Mt. Watatic 
and Concord, R. H. Howe, Jr. (Th); Arlington, B. Fink May 1895 (R); “near 
Boston,” T. P. Adams(BSNH 
Connecticut: Woodbridge, G. E. Nichols March 13, 1909 (R). 
New York: Adirondack Mts., Mrs. C. W. Harris 1900 (R); L. W. Riddle 
Aug. 1908 (R). 
Onto: Lesquereux? (NY). 
Micuican: E. T. Harper Aug. 1899 (R). 
Wisconsin: C. F. Baker (CEC). 
Minnesota: Macmillan 1804 (R); B. Fink July 30, 1902 (R). 
Orecon: EF, Hall 1871 (Tuck). 
TucKERMAN, following Tu. Fries, cites E. Fries as the author of this 
species. The combination was first made, however, by AcHARIUS (0. cit.), 
who refers to the figure in English botany, pl. 282. According to the Vienna 
Code (Articles 40 and 41), AcHartus should be cited therefore as the author, 
even though his conception of the species was later emended by Fries through 
the segregation of S. tomentosum and S. coralloides. 
S. paschale is the commonest and most widely distributed species of the 
Senus, at least in the eastern portion of North America. In the west it seems 
to be comparatively rare, its place being taken by S. tomentosum. 
The two species named may be best separated from their allies by the 
palmate-digitate type of squamules (fig. 7). The chief difficulty, however, 
cient amount of material shows that there are all gradations from wholly 
glabrous podetia through a medium amount of tomentum to densely tomentose. 
As the tomentum is the chief character hitherto used as diagnostic, it is clear 
that with such variability much confusion must result. A second character 
which has beert used is the position of the apothecia, in typical S. paschale 
