178 



The Poplars 



The leaves are broadly triangular-ovate, rather finely and bluntly toothed, pointed, 

 sometimes long-pointed, lo to 17 cm. long, firm in texture, the base truncate, 

 slightly heart-shaped or rarely broadly wedge-shaped ; when very young they are 

 somewhat hairy, but soon become smooth on both sides, bright green and shining 

 above, paler beneath; the leaf-stalks are laterally flattened and about as long as 

 the blades; the narrow stipules are i to 2.5 cm. long. The catkins are short- 

 stalked, and at flowering time in April or May are 7 to 12 cm. long, their scales 

 fringed by numerous filiform lobes, the staminate ones densely flowered and 10 to 

 12 mm. thick; the pistillate flowers are short-stalked, the disk small and appressed 

 to the ovary, which is surmounted by 3 or 4 large lobed stigmas. In ripening 

 the pistillate catkins elongate greatly, becoming 15 to 25 cm. long; the capsules 

 are ovoid, pointed, 8 to 10 mm. long, and about as long as their stalks. 



The tree grows with great rapidity, young plants often increasing in height as 

 much as 4 meters during a season. The wood is soft, weak, and brown, with a 

 specific gravity of about 0.39; it is used for boxes and for paper-pulp. M. Dode, 

 a French dendrologist, has expressed the view that the Carolina poplar can be di- 

 vided into several species. 



15. WESTERN COTTONWOOD — Populus Saigentii Dode 



Populus deltoides occidentalis Rydberg 



This species is very closely related to Populus deltoides Marshall, of which it 

 has been regarded as a variety. It is a very large tree, with spreading branches, 



and inhabits river bottoms 

 from Saskatchewan and Al- 

 berta to South Dakota, Ne- 

 braska, Kansas, Colorado, and 

 New Mexico. 



The bark is gray, that of 

 old trees thick. The young 

 twigs are smooth, greenish, be- 

 coming light yellow and shin- 

 ing. The buds are glutinous, 

 pointed, the terminal ones i 

 cm. long or more. The leaves 

 are smooth on both sides 

 when mature, broadly triangu- 

 lar, commonly wider than 

 long, rather long- pointed, 

 coarsely and blimtly toothed. 



Fig. 136. — Western Cottonwood. 



except at the apex and base, 10 cm. long or less, the base usually more or less 

 kidney-shaped, varying to truncate; there are sometimes 2 very small glands at 

 the base of the blade on the upper surface; the leaf -stalks are much flattened side- 



