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BETULACE.E. (BIRCH FAMILY.) 
summer branchlets downy and nearly orbicular ; fruiting catkins cy¬ 
lindrical; the scales more or less unequally 3-lobed; fruit broadly 
winged. (B. glandulbsa, Michx.)— Bogs, N. New England (rare), 
Penn., Ohio, Michigan, and northward. — Shrub 2° - 5° high, with 
smooth, or sometimes resinous-warty, branchlets; the growing twigs 
downy. Leaves thickish, 1' -1£' long, pale or whitish underneath. 
7. B. liana, L. (Dwarf or Alpine Birch.) Branches spread¬ 
ing or procumbent; leaves orbicular , deeply crenate, smooth, reticu¬ 
lated-veiny underneath; fruiting catkins oblong; the scales nearly 
equally 3-cleft; fruit narrowly winged. — Alpine summits of the 
White Mountains, New Hampshire, and of Essex Mountains, New 
York. Shrub 10'- 24' high, with leaves about wide : varying, in 
less frigid stations, with the larger leaves twice that size, and the 
branchlets often conspicuously warty with resinous dots, when it is 
B. rotundifolia, Spach , and B. Littelliana, Tuckerm. 
2. ALNUS, Tourn. Alder. 
Sterile catkins elongated and drooping, with 5 bractlets and 1 to 
3 flowers under each scale, each flower usually with a 4-parted 
calyx and 4 stamens : filaments very short: anthers 2-celled. 
Fertile catkins ovoid or oblong ; the fleshy scales each 2-flowered, 
with a calyx of 4 little scales coherent with the scales or bracts of 
the catkin, which are thick and woody in fruit, all coherent below, 
and persistent. — Shrubs or small trees, with stalked leaf-buds 
furnished with a single scale, and the (often racemed or clustered) 
catkins of both sorts produced at the close of summer, remaining 
entirely naked through the winter, and expanding in early spring. 
(The ancient Latin name.) 
§ 1. Alnus proper. — Fruit wingless. 
1. A. incana, Willd. (Speckled or Hoary Alder.) Leaves 
broadly oval or ovate , rounded at the base , sharply serrate, often coarse¬ 
ly toothed, whitened and mostly downy underneath ; stipules oblong- 
lanceolate; fertile catkins oval; fruit orbicular. (A. gladca, Michx.) 
— Shrub 8^-20° high, forming thickets along streams, the common 
Alder northward from New England to Wisconsin. — The var. glau- 
ca has the leaves pale, but when old quite smooth, underneath. 
2- A# serrulata, Ait. (Smooth Alder.) Leaves obovate , 
acute at the base, sharply serrate with minute teeth, thickish, smooth 
and green both sides , a little hairy on the veins beneath; stipules oval; 
fertile catkins ovoid-oblong; fruit ovate. — Shrub 6°-12° high, in 
similar situations to the preceding; the common Alder of Southern 
New England, New York, Ohio, and southward. 
