614 BETULACE2 BETULA 
1 BETULA L., Sp. 982. 
Trees or shrubs with smooth or laminated outer bark, toothed 
simple leaves and small flowers appearing with or before the leaves. 
Staminate aments long and drooping, solitary or in pairs, from 
lateral or terminal leafless buds the flowers about 3 together in the 
axil of each shiéld-shaped bract, consisting of a membranaceous 
usually 4-toothed calyx and 2 stamens, subtended by 2 bractlets: 
filament short, deeply 2-cleft, each fork bearing an anther-cell. 
Pistillate aments oblong to cylindrical, solitary or racemose, from 
lateral 3-5-leaved buds, the flowers 1-3 in the axil of each bract, 
without calyx. Bracts usually 3-lobed and falling with the seed. «© 
Ovary sessile: styles 2, stigmatic at the apex, mostly persistent. 
Nuts small, lenticular, surrounded by a wing. 
B. occidentalis Hook. Fl. ii, 155. A small or middlesized tree 20-60 
feet high and 6-18 inches in diameter, with smooth dark brown bark and 
greenish-brown warty twigs: leaves broadly ovate to nearly orbicular, acute | 
to rounded at the apex, sharply serrate, the teeth glandular tipped, round- 
ed or obtuse at base, short-petioled glabrous, or sparingly pubescent on 
one or both sides, 1-2 inches long: staminate aments usually 3 together at 
the ends of slender branchlets, 2-3 inches long: pistillate aments mani- 
festly peduncled, cylindric, spreading or pendent, 12-18 lines long, 4-6 lines 
in diameter when mature: fruiting bracts ciliate, 2-3 lines long. their lat- 
eral lobes ascending, usually shorter than the middle one: nutlets much 
narrower than the wings. Along streams in the interior, Brit. Columbia 
to California and Nebraska. As here defined perhaps includes more than 
one species. » : 
B. Hallii. B. glandulosa of authors as to the Oregon plant. An erect 
shrub 4-10 feet high, the twigs ashy-gray, glandular and somewhat pubes- 
cent, very leafy: leaves obovate, rounded at the apex, cuneately narrowed 
at base into short petioles, green and glabrous both sides, finely serrate, 
10-12 lines long: pistillate aments cylindric, erect or barely spreading, 
10-1+ lines long; 2-3 lines thick, dark green, on slender peduncles 4-6 lines 
long: fruiting bracts a line long, glabrous, the lateral lobes usually broader 
than the middle one which is spreading and hyaline-margined: nutlets as 
broad or broader than long, narrowly winged. Lake Labish, Marion Co. 
Oregon: specimens collected by Mr. Gorman at Ft. Selkirk, Yukon Ter. 
appear to be of this species. 
2 ALNUS Gertn. Fr. & Sem. ii, 54, t. 90. (1791.) 
Shrubs or trees with alternate serrate or dentate leaves and 
small flowers in aments, opening with or before the leaves, mak- 
ing their first appearance during the previous season. Staminate 
aments fascicled, drooping. Bracts shield-shaped, stipitate, in- 
cluding the 5 bractlets and usually 3 flowers with regular 4-lobed 
calyx. Stamens 4, inserted opposite the lobes of the calyx, with 
very short filaments and contiguous anther-cells. Pistillate a- 
ments panicled, short and usually erect, their bracts fleshy and 
imbricated, including 4 bractlets and 2 flowers, connate and 
slightly 4-lobed, in fruit woody and persistent, thickened and 
truncate at the apex, at length divergent. Nutlets compressed, 
mostly wingless or nearly so. 
A. Oregana Nutt. Sylva, i, 28. A. rubra Bong. A large tree 50-100 
