BETULACE^E 



with ovate acute scales apiculate at apex, puberulous on the outer surface; pistillate aments, 

 i'-f' long, about iV thick, on slender glandular pubescent peduncles f'-f in length; scales 

 acuminate light green strongly reflexed; styles bright red. Fruit: strobiles cylindric, gla- 

 brous, 1' long, their scales ciliate on the margins; nut oval, somewhat narrower than its 

 thin wing. 



A tree, 30-40 high, with a trunk 12'-20' in diameter, wide-spreading branches, stout 

 branchlets marked by numerous small pale lenticels, bright red-brown during 2 or 3 years, 

 gradually becoming darker. Bark thin, more or less furrowed, very dark brown or nearly 

 black near the base of the trunk, grayish white or light reddish brown and separating into 

 thin layers higher on the stem and on the branches. 



Distribution. Coast of Alaska from Cook Inlet southward to the head of the Lynn 

 Canal. 



7. Betula alaskana Sarg. White Birch. 



Leaves rhombic to deltoid-ovate, long-pointed, truncate, rounded or broadly cuneate, 

 or on leading shoots occasionally cordate at the entire base, coarsely and often doubly 

 glandular-serrate, thin, dark green above, pale and yellow-green below, l|'-3' long, I'-l^' 

 wide, with a slender midrib and primary veins pubescent or ultimately glabrous be- 

 low; petioles often bright red, somewhat hairy at first, finally glabrous, about 1' long; 

 Flowers: staminate aments clustered, sessile, 1' long, |' thick, with ovate acuminate scales 





Fig. 205 



puberulous on the outer surface, and bright red, with yellow margins; pistillate aments slen- 

 der, cylindric, glandular, 1' long, f ' thick, on stout peduncles nearly y in length. Fruit: 

 strobiles glabrous, pendulous or spreading, I'-lj' long, f '-' thick, their scales ciliate on 

 the margins; nut oval, narrower than its broad wing. 



A tree, usually 30-40, occasionally 80, high, with a trunk 6'-12' in diameter, slender 

 erect and spreading or pendulous branches, and glabrous bright red-brown branchlets more 

 or less thickly covered during their first year with resinous glands sometimes persistent 

 until the second or third season. Winter-buds ovoid, obtuse at the gradually narrowed 

 apex, about \' long, with light red-brown shining outer scales sometimes ciliate on the 

 margins, and oblong rounded scarious inner scales hardly more than \' long when fully 

 grown. Bark thin, marked by numerous elongated dark slightly raised lenticels, dull red- 

 dish brown or sometimes nearly white on the outer surface, light red on the inner surface, 

 close and firm, finally separable into thin plate-like scales. 



Distribution. Valley of the Saskatchewan northwestward to the valley of the Yukon, 



