78 CHINESK ECONOMIC TEEES 



acuminate, simply or doubly serrate, glabrous or pubescent below with 

 tufted hairs on the axils of the veins, 5-7 cm. long, 3.5-6 cm. wide; 

 petioles 1.5-2 cm. long. Strobile solitary, about 2.5 cm. long. Nutlet 

 oblong or ovate-oblong with thin, transparent wings. 

 N. E. Asia. China: Chihli. 



Several varieties of this tree have been distinguished, but for all 

 practical purposes they may be disregarded by foresters. 



Propagated by seeds. The number of seeds per lb. is about 777,600. 



Betula davurica Pallas. 



Tree 20 m. tall. Bark purplish-brown. Branchlets hairy, glandular. 

 Leaves about 8 cm. long, narrow ovate to ovate-rhombic, acute, cuneate 

 at the base, irregularly serrate, pubescent along the veins beneath. 

 Strobile ovoid-cylindric with glabrous scales ; nutlets very narrow winged. 



Amurland, Manchuria, Korea, Japan, and N. China. 



This tree is distinguished by the shaggy, purplish-brown bark. 



Betula albo— sinensis Burkill. 

 (B. utilis var sinensis Winkler.) 



Tree 30 m. tall with orange-red bark and glabrous, shiny branchlets. 

 Leaves ovate, acuminate, doubly serrate, rounded at the base, somewhat 

 glabrous beneath, with 9-10 pairs of veins, 4-8 cm. long. Cones cylindric, 

 about 4 cm. long. 



Central and W. China. 



Betula alnoides Hamilton. 



Tree 20 m. tall with brown bark. Branchlets pubescent. Leaves 

 glossy green, glabrous or nearly so, ovate-oblong to lanceolate, 6-16 cm. 

 long, doubly serrate, with 10-13 pairs of veins 



Allied to B. maximowiczii. 



India to Yunnan. 



Betula luminifera Winkler. 



Tree 20 m. tall with smooth yellow-gray to reddish-brown bark. 

 Leaves ovate, subcordate, serrate with acute teeth, 8-13 cm. long. Strobile 

 solitary, 5-8 cm. long. 



