428 



Butler: The western American birches 



latter has leaves mostly acute at the apex and the branchlets are 

 more resinous and more hairy. In B. obovata the branchlets are 

 mostly glabrous with occasionally a very few coarse hairs. 



6. Betula Hallii Howell, FL N. W. America i: 614. 



1902 



A shrub 1-3.5 ni. high with ashy gray branchlets ; twigs finely 

 pubescent to velvety-pubescent, sparingly glandular-resiniferous ; 

 leaf- blades about 4 cm. long and 2.5 cm. wide, obovate, with rounded 



-Figure 5. Betula obo- 



vata Butler. From type, B, 



T. Butler jij, Ravalli, 



Mont 



Figure 6. Betula Hallii 

 Howell. From E. Hall ^bg, 

 Lalce Labish, Oregon. 



ana. 



apex and cuneate base, crenate to crenate-serrate with fine teeth, 

 green and glabrous on both sides, with very numerous minute resin- 

 dots beneath.; petioles short, sometimes with a few scattered hairs ; 

 fruiting aments about 4 cm. long and 5-6 mm. thick, very slender ; 

 bractlets about 4 mm. long and 3 mm. wide, glabrous, the lobes 

 narrow, obtuse or truncate, usually of about equal length and 

 width ; samara 1-2 mm. wide, wing narrower than the oval or 



obovate nutlet. 



[Figure 6. 1 



4.60 



Labish, Marion Co., Oregon. Howell cites the above locality but 



gives no herbarium number. 



One would infer that the above 

 number of Hall's would be at least a cotype. Howell describes 

 the leaves as finely serrate but in all specimens I have examined 

 they are more nearly crenate. H. Winkler in Das Pflanzenreich. 



61 



4 



Winkler 



pitmila 



It is distinguished by the long slender fruiting aments ; gla- 



