Salicaceae. 



33 



ORDER 70. — Salicaceae. 



Flowers dioecious seldom monoecious, in catkins which appear before the 

 leaves. Stamens i or more. Ovary i -celled. Styles 2 short. Stigmas 2. 

 Each flower in the axil of a small scale-like bract. Leaves alternate stipulate. 



Catkins drooping, Populus I. 



Catkins erect, Salix II. 



\.— POPULUS. 



Catkins drooping, scales crenate lobed or cut, stamens 4 — 30 from the 

 oblique cup-like disk, stigmas slender 2 — 4-cleft. 



Young shoots pubescent, 512 



Young shoots glabrous, .... 



512 Leaves white and cottony beneath, 



512 Leaves glabrous or silky beneath, . 



POP'ULUS NI'GRA. Black Poplar. 3—4. 

 (1314) finely serrate, petiole slender compressed. 



POP'ULUS AL'BA (60). W^ite Poplar. 3—4. Leaves broadly ovato- 

 (1311) cordate lobed and toothed white beneath. Moist woods. 



POFULUS TREM'ULA (100). Aspen. 3—4. Leaves nearly round 

 (13 1 3) acute serrate glabrous beneath, petiole very long and slender com- 

 pressed. Moist woods. 



P. nigra. 



P. alba. 



. P. tremula. 



Leaves triangular crenate 

 River banks. 



\\.— SALIX. 



Catkins erect, scales entire, stamens 2 — 5, fruit a i -celled follicle, seeds 

 hairy. 



