LIBRARY 



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THE OTTAWA NATURALIST 



VOL. XXIV. OTTAWA, MAY, 1910 No. 2 



CANADIAN SPECIES OF THALICTRUM. III.* 



By Edward L. Greene. 



A most difficult chapter in the past history of Canadian 

 meadow-rues is that relating to the summer-blooming white- 

 flowered kinds; tall plants, usually inhabiting wet meadows or 

 banks, and not coming into flower until early summer, their 

 panicles often ample and of a plumy whiteness, making their 

 fine display at a time when the early kinds, always green- 

 flowered and inconspicuous, have passed to the fruiting stage. 



The whiteness of the panicles of these white-flowered kinds 

 is due to the fact that the numerous filaments that-make up the 

 bulk of the flowers are flattened, or at least thickened above, and 

 are of a pure white, thus resembling in some degree narrow 

 petals; and they even stand upright, after the manner of petals, 

 whereas the filaments of the vernal green-flowered sorts are 

 finely capillary and altogether pendulous. 



Some member of this white-stamened group appears to 

 have been the first among American meadow-rues to gain a 

 place in European gardens. As early as the year 1635 there 

 grew and flowered in Paris a Canadian meadow-rue with up- 

 right white stamens, and the name of it as Thalictrum Canadense 

 was published in that year, at Paris, in a book on Canadian 

 plants with the Latin title: Canadensium Plantarum Historia. 

 If the printing of the name had been accompanied by an adequate 

 description of the plant, we should have had here the beginning 

 of the written history of some one of the several white-stamened 

 meadow-rues of Canada; for, by such description the competent 

 botanist of to-day might have identified some one or another of 

 them as the T. Canadense of Cornut. That early description is 

 not, however, of the least help to us in that direction, and all 

 for the reason that said author, at least as to the fruit, describes 

 precisely that of a familiar white-stamened European species 



* C". Ott. Xat. xxiii. 17, 37. 



