April, 1912.] 
North American Ly copods 
499 
Photographs of what are regarded as typical examples are here 
presented. The English plant was from Tilgate forest, Sussex. 
Both the American and European plant show plainly that the 
branching habit of L. selago is similar to that of L. lucidulum. 
The branching is a successive dichotomy at rather regular intervals. 
In the European specimens the leaves are smoother and more 
rigid in appearance than in the Alaskan plants. In the Alaskan 
specimens the leaves are slightly crinkled and not so rigid and the 
surface has a silky-glossy appearance. Specimens in the Ohio 
State Herbarium from Europe and from the Roan -Mountains of 
North Carolina show the same differences. The Ohio specimens 
of L. porophilum do not show the crinkled character nor the silky- 
glossy surface of the American L. selago. Although there is a 
slight difference between the American and European L. selago, 
it is too insignificant to be considered. 
Fig. 3. Lycopodium selago, from Tilgate Forest, Sussex. England. 
Fig. 4. Lycopodium selago, from Alaska. Photograph by Forest B. H. 
Brown. 
L. porophilum is readily distinguished from L. selago by its 
mode of branching and by its reflexed lower leaves. Mature 
specimens seem, however, to be frequently included with L. 
selago in collections. 
As stated above, incorrect determinations may easily be made 
from young specimens, but the recapitulation of ancestral charac- 
ters does not invalidate a species that is well differentiated at 
maturity. The figures presented above show that we have in 
America three very characteristic forms of the group of Lycopods 
under consideration each of which is distinct enough to be regarded 
as a valid species. 
