Butler : The western American birches 427 



mm, wide, claw long, cuneate, lobes rounded, about equal in width, 

 the middle usually but a little longer than the ascending lateral 

 ones ; samara 3-4 mm. wide, the wings much wider than the 

 narrowly oval nutlet. [Figure 4.] 



Type, B. T, Butler ^og, from a swamp near Rost Lake, Mon- 

 tana, — in herbarium of the N. Y. Botanical Garden. 



This has been determined as Betula puviila^ from which it dif- 

 fers in having less pubescent, more or less glandular branchlets ; 

 nearly glabrous, never pubescent, oval leaves ; bractlets differing 

 in size and form ; and in the broadly winged samaras. It is abun- 

 dant in the type locality, forming small clumps about the swampy 



borders of small ponds and lakes in the eastern Flathead Valley. 



It is with pleasure that the name of Dr. Morton J. Elrod, well 



known in connection with the natural history of the Flathead 



r 



region of Montana^ is given to this distinct species. 



5 /Betula obovata sp. no v. 



A rather coarse shrub with rough dull gray bark and very 

 small inconspicuous lenticels ; branchlets slender, puberulent, but 

 not hairy excepting a few scattered long hairs occasionally on 

 young shoots, sparingly glandular-resiniferous, red-brown, becom- 

 ing gray; leaf-blades 2-4 cm. long, 1.5-3.5 ^^- wide, thick, firm, 

 dark, shining and reticulated above, paler and dull green beneath, 

 obovate, serrate or crenate-serrate with irregular teeth 1-4 mm. 

 wide, apex rounded, base cuneate, venation coarse and conspicu- 

 ous, veins 5 or 6 pairs, surface pubescent beneath especially along 

 midrib and veins, often with longer scattered hairs on basal margin 

 and along midrib, minute resin-dots beneath ; petioles reddish 

 brown, pubescent or with coarse hairs, 5-10 mm. long; fruiting 

 ament cylindrical or oval, obtuse at each end, 2-2.5 cm. long, 6- 

 8 mm. thick, stalk 6-8 mm, long; bractlets puberulent, ciliate, 

 3-5 mm. long, 2-3 mm. w^ide, middle lobe long-ovate or triangu- 

 lar, obtuse or subacute, lateral lobes obliquely rhombic or ovate, 

 acute or subacute ; samara 3-5 mm, wide, wing as broad as or 

 mostly broader than the oval or obovate nutlet. [Figure 5.] 



Type, B, T. Butler jij, valley of the Jocko River, Ravalli, 



Montana, — in herbarium of the N. Y. Botanical Garden. 



' This species is distinguished by its dark, shining, obovate, 



coarsely serrate leaves, rounded at the apex, and the broad-winged 



samaras. " The fruit resembles that of Betula fontinalis, while the 



leaves and branchlets resemble those of B. glandtdifcra. The 



