Butler: The western American birches 



439 



tipped teeth, veios 6-8 pairs, impressed above, conspicuous and 

 hairy beneath with small tufts of hairs in the axils, lower surface 

 with numerous small resin-dots, the basal margins sometimes hairy ; 

 petioles 1-2 cm. long, puberulent, often with a few scattered hairs ; 

 fruiting ament 2.5-3.5 c"^- ^^ng, about i cm. thick, cylindrical or 

 narrowly oval, narrowed toward the rounded base and apex, 

 stalks slender, 10-15 mm. long, puberulent and resinous; bractlets 



Figure 17. Betula montanensis Butler. From type, B. T. Butler j6o^ Yellow 

 Bay, Flathead Lake, Montana. 



puberulent or pubescent, strongly ciliate, 5-7 mm. long, about 3 

 mm. wide, broadest at the base of the spreading obliquely rhombic, 

 rounded, lateral lobes, middle lobe acute or obtuse, triangular, 

 long and tapering, claw elongated, cuneate; samaras about 4 mm. 

 wide, wings broader than the oval, puberulent nutlet. [Figure 



Type, B. T, Butler j6o, collected at Yellow Bay, eastern shore 

 of Flathead Lake, Montana, and deposited in the herbarium of 



the N. Y. Botanical Garden. 



This is distinguished by its thick dull green somewhat lobed 

 truncate leaves and its non-peeling dark gray bark. In appear- 

 ance the trunk suggests the alder with its mottled gray and brown 



