248 



The Birches 



green and warty-glandular, becoming smooth and yellowish to reddish brown. 

 The buds are ovoid, 4 mm. long. The leaves are triangular-ovate to rhombic- 

 ovate, hain^, at least on tlic veins of the lower surface when young, nearly or quite 

 smooth when fully grown, irregularly and often doubly toothed, and taper into a 

 long toothed tip; they are blunt or truncate at the base, bright green and shining 

 above, pale green beneath, and vary from 3 to 7 cm. in length; the very slender 



Fig. 203. Gray Birch, Van Cortlandt Park, N. Y. City. 



leaf-stalks are 1.5 to 3 cm. long, . stipules ovate and pointed. The leaves quiver 

 in a light breeze, like those of Asp. . The tree flowers in April or May. The 

 staminate catkins are 5 to 10 cm. long, usually solitary, rarely two together. The 

 ripe pistillate catkins (strobiles) arc cylindric, 1.5 to 3.6 cm. long, on stalks about i 

 cm. long; their scales are finely hairy, 2 to 4 mm. long, the lateral lobes larger than 

 the middle one; the nut is oval, about 2.5 mm. long, and narrower than its wings. 

 The wood is light brown, soft and weak, with a specific gravity of about 0.58; 



