282 



BOTANICAL GAZETTE 



[OCTOBER 



POPULUS DELTOIDES 



Leaf 



Stem 



M 

 T 193 fi (177-227) 



X 



254 M (236-295) 



M 



UE. 

 P... 



13 



62 



7 per cent 



18 



7 per cent 



32 



Sp 105 =54 



LE. . .. 13 



OW... 2.3 



Cu. . . 0.8 



84 =33 

 138 = 55 



14 

 4 



5 



i-3 



N. . 



D.. 

 W.. 

 F... 



JL*» ■ . 



R.. 



46 



49 

 2.6 



3-8 

 6.8 



M(6 4 ) 



82 



S. . . . 94 



85 



50 A* (62) 

 2.7 



3-9 

 6 



i-4 



105 

 98 



In both lower epidermis thickened as 



Agreeing with the majority in all 



well as upper, stomata on both surfaces points; a tendency to angled twigs and 

 and side walls of epidermal cells plane, all star-shaped pith more marked in X. 

 related to the movement of the leaf. 

 X. — Upper epidermal cells smaller in 

 surface; surface slightly hairy; palisade 

 sometimes triple; also palisade cells near 

 lower epidermis, separated from it by a 

 layer of heavily walled cells, like a second- 

 ary epidermis. Other points follow the 

 general rule. — Figs. 14 and 15. 



14 



Figs. 14, 15. — Populus deltoidcs: sec- 

 tions of leaves; fig. 14, mesophytic form; 

 fig. 15, dune form. 



15 



