Proceedings of the Ohio State Academy of Science 125 



of basal brittle zones. The charcoal from the larger species used 

 for making gunpowder. 



1. Twigs decidedly pendulous or "weeping", green or yellowish-green; 

 leaves linear-lanceolate, acuminate, serrulate, smooth, rather pale 

 beneath, petioles glandular above ; capsule glabrous, pedicel very 

 short, stigma sessile. ^. babylonica. 



1 . Twigs not pendulous nor weeping, but some may be drooping. 2. 



2. Leaves tapering to the short petioled or nearly sessile base, linear- 



lanceolate, remotely denticulate, coarsely silky when young, usu- 

 ally glabrate in age ; shrubs or small trees with a narrow, slender 

 crown; capsule glabrous or silky; stamens 2. S. Huviatilis. 



2. Petioles present and rather prominent and slender except in some 



individuals. 3. 



3. Leaves silky, tomentose, or hairy below when mature; stamens 2. 4. 



3. Leaves glabrous below, or nearly so, when mature, sometimes finely 



pubescent when young. 5. 



4. Leaves long linear-lanceolate, sparingly repand-crenulate, or entire, 



white or silvery silky beneath, without glands on the petiole, acu- 

 minate ; twigs terete, green ; capsule nearly sessile, silky or to- 

 mentose. style long. S. vhninalis. 

 4. Leaves lanceolate, narrowed at the base, serrulate, silky pubescent 

 and glaucous beneath, usually w'ith glands on the petiole at the 

 base of the blade ; capsule glabrous, pedicel very short, stigma 

 sessile. 5". alba. 



4. Leaves ovate-lanceolate, slender-pointed, firm, pubescent or white- 



tomentose beneath, sharply serrate or entire ; bracts j'ellow, linear- 

 oblong or lanceolate ; capsule silky or tomentose, pedicel filiform. 

 6". bebbiana. 



5. Petioles usually witliout glands, or if with glands then the leaves 



of tlie ovate type and short pointed ; stamens 2. 7. 



5 . Petioles usually with glands on the top or at the base of the blade ; 



stamens 3-12, in one species 2 ; capsule glabrous. 8. 

 G. Length of leaf-blade less than 3 times its breadth; mature leaves 

 thin and dull, elliptic, ovate-oval, or obovate, acute or obtuse at 

 the apex ; stamens 2. 5". balsamifcra. 



6. Length of leaf-blade 3 times its breadth or more. 7. 



7. Leaves oblanceolate or spatulate, acute, serrulate, somewhat glaucous 



beneath; twigs purplish, flexible; filaments of stamens united; 

 capsule silky or tomentose, sessile ; stigma sessile. S. purpurea. 

 7. Leaves lanceolate or oblanceolate, acuminate, finely serrate with mi- 

 nute gland-tipped teeth, pale and glaucous beneath ; twigs of the 

 season pubescent or puberulent ; capsule glabrous. S. niissouriensis. 



