426 Salicace.e. 



c Capsules glabrous ; leaves 



d Oblong-lauceolate, acute at apex S. balsamifera. 



d' Linear-lanceolate ; branchlets long and pendent S. Babylonica. 



d^ Lanceolate to oblanceolate ; branchlets not pendent, 

 e (ilabrous 



Bright or reddish yellow ; leaves glaucous beneath S. vitellina. 



Light brown ; leaves silky pubescent S. alba. 



e- Brownish pubescent S. Missouriensis. 



c' Capsules hairy ; style short ; leaves ovate-lanceolate to oblong, acute 



Glabrous and glaucous beneath ; branchlets usually glabrous ; pedicel of ovary shorter 



than the scale S. discolor. 



Pubescent beneath ; branchlets pubescent ; pedicel of ovary longer than scale. 



S. Bebbiana. 

 For species see pp. 7Jf-93 and the foUoicing : 



Balsam Willow. Salix halsamifera Barr. A species of boreal distribution ranging 



from about the latitude of Mt. Washington northward and usually shrubby, but in the 



vicinity of Ft. Kent, Me., has been found to attain the height of 25 ft. with trunk 12-14 in. 



in diamater. It is characterized as follows : 



Leaves elliptic to ovate, 2-4 in. long, rounded or subcordate at base, usually acute or 

 obtuse at apex, finely glandular-serrate, thin at first, finally rigid, glabrous, dark green above, 

 paler, glaucous and prominently reticulated beneath : stipules usually none : petioles slender 

 1/2 in. or less in length. Floicers : aments expanding with the leaves on leafy-bracted 

 branchlets, the staminate dense ; stamens 2, with free filaments ; pistillate rather loose : scales 

 rose-colored, villous, persistent ; style very short. Fruit capsules narrow-ovoid, long-stalked. 



White Willow. SaJix alba L. A large European tree willow sparingly escaped in 

 this country and differs from the >S'. vitelUita mainly in having more ashy gray and silky 

 pubescent leaves, which gives a whitish effect to its foliage, and more brownish branchlets. 

 Var. eaeriilea Koch., also occasionally found, has more glabrous dull bluish green leaves and 

 olive branchlets. 



Bebb Willow. Salix Bebhinana Sarg. (,S'. rostrata Rich. I. A large shrub or small bushy 

 tree, occasionally 25 ft. in height, with a trunk fi or 8 in. in diameter, ranging from Pennsyl- 

 vania to the Arctic regions, and from the St. Lawrence River to Alaska, and in botanical 

 characters is close to <S'. discolor (see pp. 92-93) but differs in having leaves uusally tomen- 

 tose or pubescent beneath ; pedicel of the ovary longer than the scale and branchlets pubes- 

 cent. 



THE POPLARS AND COTTONWOODS. Genus POPULUS L. 



Trees of usually large size, rapid growth, with scaly and usually resin-coated buds and 

 bark pale at first but furrowed when old and rich in tannin. The sticky resin of these buds 

 is gathered by honey bees for sealing crevices in their hives, the material which bee-keepers 

 call " propolis." About twenty-five species are recognized of which approximately half are 

 natives of North America ranging from the Atlantic to the Pacific and from the Arctic Circle 

 to the tropics. 



The Poplars are the oldest known dicotyledonous plants, being represented among the 

 ills of the cretaceous formations. 



Leaves lance-ovate to orbicular or deltoid, involute in the bud, usually with long stalks 

 more or less laterally compressed causing their easy agitation by the winds : stipules small 

 and caducous ; branchlets terete or angled ; winter buds pointed, more or le.ss resin-coated 

 and covered with several thin imbricated scales. Floicers expanding with or before the leaves 

 in stalked drooping aments which elongate while maturing, with thin obovate stipitate 

 fimbriated caducous scales, more crowded on the staminate aments; pistillate aments with 

 broad cup-shaped, usually oblique, stipitate and persistent disk ; stamens 4-r)0. with short free 

 filaments: anthers purplish: ovary sessile with short style and entire digitate or broadly 

 2-4-lobed stigma. Fruit maturing often before the full growth of the leaves, in usually 

 drooping racemes and with subglobose to ovoid-oblong capsules subtended by the persistent 

 disk and dehiscent by 2-4 recurved valves; seeds small, brown and provided with abundant 

 cottony hairs. 



The name is the ancient Latin name of the Poplar. 



KEY TO THE SPECIES. 



a l?uds coated with a sticky resin ; leaves 



b Broadly deltoid, acute or acuminate at apex 



Very wide-cordate to truncate at base : buds large P. deltoides. 



Verv wide-cuneate to truncate at base: buds comparatively small. 



P. dilatata. 



V Rhombic-lanceolate, green both sides, long-pointed P. acuminata. 



V Ovate-lanceolate, green both sides, short-petiolate P. angustifolia. 



