76 



PROCEEDINGS OF THE AMERICAN ACADEMY 



S. eriocephala, related to S. daphnoides 

 S. brachystachys, " 



S. discolor, ) ^^ 



S. macrocarpa^ ) 



S. aurita. 



S. phylicifolia. 



S. vagans. 



S. repens. 



S. rosmarinifoUa. 



S. Geyeriana, " 



S. humilis, ) 

 jS. tristis, \ 



S. gracilis, " 



S. suhcordata, " 



& Pseudo-Myrsinites, ) 

 iS. cuHi flora, \ 



S. Cutleri, " 



IV. Those which also manifestly represent European types, but with 

 more marked specific differences than those under the preceding 

 head : 



S. glauca. 



S. Myrsinites. 

 S. myrtilloides ? 



belonging to the type of S. daphnoides. 



" S. lanata. 



" S. Lapponum. 



"■ S. laurina. 



" S. hastata. 



" S. glatica. 



S. Bigelovii, 



S. lasiolepis, 



S. Coidteri, 



S. Hoolceriana, ) 



S. speciosa, \ 



S. Candida, " " " 



S. Drummondiana, " " "■ 



S. adenophylla, " " " 



S. Barclayi, " " " 



V. Those which form peculiarly American types : 



1. S. longifolia, S. sessilifolia (* Hindsiana and S. taxifolia). Cor- 

 respondents in Europe, S. riparia and its allies. To which may 

 be added S. nigra and S. longipes, belonging to a type peculiar to 

 southern or tropical countries. 



2. S. Sitchensis, S. serica (grisea), and S. petiolaris ; compensations, 

 as it were, in America, for our Salices mollissimce and repentes. 

 (S. angustifolia, Wulf., is by Wimmer and otliers regarded as a 

 hybrid of S. repens and <S. vimincdis.) 



3. S. rhamnifolia, S. ovalifolia, S. glacialis, and S. myrtillifolia, — 

 purely arctic forms, corresponding only with species from northern 

 or arctic Siberia. 



From all this we gather, that, of the fifty-eight species growing in 

 North America, there are 



