759 



P. berolinensis, Dispel. Origin uncertain. 

 P. laurifolia var. berolinensis, Hort. 

 P. hybrida var. berolinensis, G. Koch. 

 P. balsamifera berolinensis, Hort. 

 P laurifolia x deltoidea ? 



P. canescens, Sm. ; Eng. Bot. ed. 3, 1. 1300. " Gray Poplar. 17 



P. albo-tremula, Krausse. 

 P. certinensis, Hort. Garden origin. 



P. deltoidea, Marsh. ; Sargent Silva of North America 

 tt. 4^4, 495. North America. " Cotton wood." 



P. Acladesca, Lindl. 

 P. angulata, Ait. 

 P. angulosa, Michx. 

 P. canadensis, Moench. 

 P. carolinensis, Moench. 

 P. cordata, Hort. 



P. dilatata var. carolinensis, Willd. 

 P. glandulosa, Moench. 

 . P. heterophylla, Duroi (not L.). 

 P. laevigata, Ait. 

 P. latifolia, Moench. 

 P. macrophylla, Hort. 

 P. marylandica, Base. 

 P. monilifera, Ait. 

 P. nigra, Marsh, (not L.). 

 P. nigra var. helvetica, Pair. 

 P nigra var. virginiana, Castigl. 

 P. serotina, Hartig. 

 P. virginiana, Fouger. 



