BETULACE^E 



215 



conspicuous tufts of axillary hairs below, 3'-5' long, 2'-2' wide; petioles puberulous, 

 f'-l' in length. Flowers unknown. Fruit: strobiles cylindric, If '-2' long, |' thick, 

 pendent on puberulous peduncles \'-\' in length, their scales puberulous, finely ciliate on 



Fig. 202 



the margins, the slender base of those below the middle of the ament rather more than 

 twice as long as the expanded upper portion of the scale. 



A tree 40-50 high, with a trunk 12'-18' in diameter, and slender branchlets red-brown, 

 lustrous, marked by small pale lenticels and puberulous during their first season. Winter- 

 buds narrow-obovoid, acuminate, dark red-brown, resinous, \' long. Bark white, or dark 

 gray or brown. 



Distribution. Shore of Yellow Bay, Flathead Lake, Flathead County, Montana, and 

 at Sandpoint, Bonner County, Idaho. 



Betula papyrifera var. occidentalis Sarg. 

 Betula occidentalis Hook. 



Leaves ovate> acute, or abruptly acuminate at apex, rounded or occasionally cordate 

 or rarely cuneate at the broad base, coarsely and generally doubly serrate with straight or 

 incurved glandular teeth, thin and firm in texture, dull dark green above, pale yellow-green 

 below, and puberulous on both sides of the stout yellow midrib and slender primary veins, 

 3'-4' long, If -2' wide; petioles stout, glandular, at first tomentose, ultimately pubescent 

 or puberulous, about f ' long; stipules oblong-obovate, rounded and acute or apisculate 

 at apex, ciliate on the margin, puberulous, glandular-viscid. Flowers : staminate aments 

 during the winter about f ' long and f' thick, with ovate scales rounded or abruptly nar- 

 rowed and acute at apex, puberulous on the outer surface, ciliate on the margins, becoming 

 3'-4' long and about \' thick; pistillate aments about 1' long and T V thick, with acuminate 

 bright green scales. Fruit: strobiles cylindric, puberulous, spreading, \\'-\\' long, \'-\' 

 thick, on stout peduncles f ' in length, their scales ciliate on the margins; nut oval, about 

 T V in length, and nearly as wide as its wings. 



A tree, 100-120 high, with a trunk 3-^ in diameter, comparatively small branches 

 often pendulous on old trees, and pale orange-brown branchlets more or less glandular and 

 coated with long pale hairs when they first appear, becoming bright orange-brown and 

 nearly destitute of glands during their first winter, and in their second year orange- 

 brown, glabrous, and very lustrous. Winter-buds acute, bright orange-brown, \'-\' long, 

 their light brown inner scales sometimes becoming f ' in length. Bark thin, marked by 

 long oblong horizontal raised lenticels, dark orange-brown or white, very lustrous, sepa- 



