54 LEAFLETS. 



its original appellation. Thus it is clear that even if Muhlen- 

 berg's T.polygamum could have been a really published name, 

 it would have had no status. It would have been long ante- 

 dated by T. Ca7iadense, Mill., and the same is true of T. 

 corynellum, DC. Again as late as 1794 Moench has the two 

 species in the Hortus Marburgensis ; and he too rejects the 

 name T. Cornuti and lists the plant under his own new appel- 

 lation of T. confertum, which also again antedates by many 

 years Muhlenberg's nomen nudum. 



The plant of the upper St. I,awrence, frequent on both the 

 Canadian side and on ours, the T. Canadense, Mill., also bet- 

 ter described by De Candolle as T. corynellum, I shall not here 

 describe anew ; but I recognize it well, and am able to distin- 

 guish from it not only the excellent T. dasycarpum of Fischer, 

 but also the following, all from regions well to the westward 

 and southward of eastern Canada and northern New England. 



The group as a whole is most unlike the Old World T. 

 aquilegifolium and its allies, as is proven by its extremely 

 different mature carpels. De Candolle well distinguished as 

 a marked subgenus, under the name Tripterium, the Old 

 World plants. It is quite as fitting that these American plants, 

 in both flower and fruit so very different from Tripterium, 

 should be designated at least subgenerically as Leucocoma, 

 in allusion to their often massive and always beautiful white 

 panicles. The whole group is aestival in its flowering, while 

 our more than equally numerous species with green flowers 

 are vernal. In respect to a number of the species there exists 

 in the herbaria no evidence of their being other than dioecious, 

 no hermaphrodite specimens occurring. Such plants I find to 

 have been commonly mistaken for the dioecious T . purpuracens , 

 so little discrimination is made by people in places of some 

 supposed authority, the clavellate filaments being overlooked 

 altogether. Again : while in the greater number of species 

 the achenes are black when ripe, and the green herbage of 

 them blackens in drying, there is one set of them marked by 

 herbage the color of which is green in the dry, and by achenes 

 that are only of an olive-green when perfectly mature. As to 



