G. 84) CLASSIFICATION AND DESCRIPTION 
6. Bétula nigra, L. (RIVER or RED 
Brrcw.) Leaves 24, to 344 in. long, 
rhombic-ovate, acute at both ends, dis- 
tinctly doubly serrate, bright green 
above; glaucous beneath when young; 
on petioles only } their length. Twigs 
brown to cinnamon-eolor, and downy 
when young. A medium-sized tree, 
30 to 50 ft. high, usually growing on 
the edges of streams, the old trunks 
having a very shaggy, loose, torn, red- 
dish-brown bark. Wild in Massachu- 
setts, south and west; often cultivated. 
Genus 84. ALNUS. 
Shrubs or small trees with deciduous, alternate, simple, 
straight-veined leaves with large stipules that remain 
most of the season. Flowers in catkins. 
Fruit a small, 
sealy, open, woody cone, remaining on the plant through- 
out the year. 
* Native species; growing in wet places. 
A. Leaves rounded at base; whitened beneath; found north of 
ALON. Mates sswiiccition gaa ues 004 ekS 
A. Leaves acute or tapering at base; southward. 
B. Flowering in the spring... ........- 
B. Flowering in the autumn ............ 
bd FRESE ES OURS 1. 
(B.) 
ERR GGE METRO 2. 
eT Cees 3. 
* Cultivated species; from Europe; will grow in dry places . .4, 5. 
cultivated. 
1. Alnus incana, Willd. (SPECKLED 
orn Hoary ALDER.) Leaves 3 to 5 in. 
long, broadly oval or ovate, rounded at 
base, sharply serrate, often coarsely 
toothed, whitened and mostly downy 
beneath; stipules lanceolate and soon 
falling. Fruit orbicular or nearly so. 
A shrub or small tree, 8 to 20 ft. high, 
with the bark of the trunk a polished 
reddish green; common along water- 
courses north of 41° N. Lat.; sometimes 
