April, 1912.] 



North American Lycopods 



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 jjlants. In the Alaskan 

 specimens the lea\-es are slightl\' crinkled and not so rigid and the 

 surface has a silk}--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. 



.*K« 



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 refiexed 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 fomis of the group of Lycopods 

 under consideration each of which is distinct enough to be regarded 

 as a valid species. 



