767 



P. trichocarpa, Hook. ; Sargent Silva of North America 

 t. 493. Western North America. " Black Cotton- 

 wood." 



P. balsamifera var. trichocarpa, S. Wats. 



P. tristis, Fisc'h. ; Dippel Laubholzk. ii. 205, f. 98. North- 

 eastern Asia. 



Yar. elongata, Koehne. 



P. candicans elongata, Dippel. 



P. Viadri, M. Ruediger. Origin uncertain. 



P. Wobstii, Schroeder. Garden origin ? 



P. balsamifera var. Wobstii, Dippel Laubholzk. ii. 207, 

 f. 101. 



Empetraceae. 



Empetrum nigrum, L. ; Eng. Bot. ed. 3, t. 1251. North 



temperate and arctic zones. " Crowberry." 

 E. crassifolium, Rafin. 

 E. procumbens, L. 



Yar. scoticum, Loud. 

 E. scoticum, Hook. 



Yar. tomentosum, Dippel. 

 E. tomentosum, Hort. 



Corema album, D. Don ; Laguna Fl. For. Esp. ii. t. 47. 

 Portugal. 



Empetrum lusitanicum, Hort. 



C. Conradii, Torr. ; Britt. & Br. Illustr. Fl. ii. 384, f. 

 Northern United States, &c. 



Empetrum Conradii, Torr. 



