48 FOUNDATIONS OF BOTANY 



young, but becoming smooth with age ; petioles cylindrical. Pistil- 

 late catkins smooth, erect, or spreading, loosely flowered. Capsule 

 ovoid, usually shorter than the pedicel. Common in river swamps. 

 A large tree with soft light wood, which is often used in making 

 cheap furniture.* 



4. P. monilifera, Ait. Cottonwood. A large and very rapidly 

 growing tree, 75 to 100 or more feet in height, often with a markedly 

 excujrent trunk. Leaves large and broadly triangular, with crenate- 

 serrate margins and long, tapering acute tips ; petioles long and 

 considerably flattened. The numerous pediceled capsules are quite 

 conspicuous when mature, and the air is filled with the downy 

 seeds at the time when the capsules open. Common W., espe- 

 cially along streams and planted as a shade-tree. 



n. SALIX, Taum. 



Shrubs or trees, branches usually very slender. Buds with 

 single scales. Leaves usually long and narrow ; stipules some- 

 times leaf-like or often small and soon deciduous; Bracts 

 of the catkins entire ; staminate catkins erect or drooping, 

 staminate flowers with 2-10, mostly 2, distinct or united 

 stamens. Pistillate catkins usually erect, flowers with a small 

 gland on the inner side of the bract, stigmas short, 2-lobed. 

 Capsule 2-valved.* 



1. S. nigra, Marsh. Black Willow. Leaves elliptical or nar- 

 rowly lanceolate, acute at each end, serrate, short-petioled, downy 

 when young and becoming smooth with age, 2-3 in. long ; stipules 

 persistent or deciduous. Staminate catkins 1-2 in. long ; the pistil- 

 late 2-4 in. long. Stamens 3-7, distinct, filaments soft, hairy below. 

 Capsule twice the length of the pedicel, ovate, taper-pointed, pointed 

 by the prominent style. A small tree with very brittle branches. 

 Along streams and borders of marshes.* 



2. S. babylonica, Tourn. Weeping Willow. Leaves narrowly 

 lanceolate, taper-pointed, serrate, slightly downy when young and 

 becoming smooth with age, green above, pale beneath, often 5-7 in. 

 long, petioles short, glandular. Catkins on short lateral branches. 

 Stamens 2. Style almost none. Capsule sessile, smooth. Introduced 

 and cultivated for ornament, becoming a large tree.* 



[Some 20 species of willow are found growing wild in the north- 

 eastern and north central states, but they are very hard, even for 

 botanists, to identify.] 



