761 



P. deltoidea cont. 

 Var. aurea, Van Geert. 



P. canadeasis aurea, Hort. 

 P. vanhoutteana, Hort. 



Var. erecta. 



P. canadensis car. erecta, Dippel. 

 P. monilifera var. erecta, Selys. 



Var. Eugenei, Nichols. 



P. canadensis var. Eugenei, Hort. Zuesch. 



P. Eugenei, Hort. 



P. pyramidalis var. meetensis, Mathieu. 



P. Fremontii, & Wats. ; Sargent Silva of North America 

 t, 496. California, &c. 



P. g-randidentata, Michx. ; Sargent Silva of North America 

 t. 488. North America. 



P. heterophylla, L. ; Sargent Silva of North America t. 489. 

 North America. " Swamp Cottonwood." 



P. argentea, Michx.f. Hist. Arb. Am. iii. 290, t. 9. 



P. balsamifera, Mill, (not L.). 



P. cordifolia, Burgsdorf. 



P. oiitariensis macrophylla, Hort. 



P. lasiocarpa, Oliver Icon. Plant, t. 1943. Central China. 



P. laurifolia, Ledeb. Altai region of Southern Siberia. 

 P. balsamifera rar. laurifolia, Wesmael. 

 P. balsamifera var. viminalis. Loud. 

 P. crispa, Hort. 

 P. crispa Lindleyi, Hort. 

 P. liiidleyana, Booth. 

 P. longifolia, Fisch. 

 P. salicifolia. Hort. 



