16. Betula glandulosa Michaux, Fl. Bor.-Amer. 2: 180. 1803.
Dwarf birch, resin birch, bouleau glanduleux Shrubs , spreading
or ascending, to 3 m. Bark dark brown, smooth, close; lenticels
pale, inconspicuous, unexpanded. Twigs without taste or odor of
wintergreen, essentially glabrous to sparsely pubescent, usually
conspicuously covered with large, warty, resinous glands. Leaf
blade mostly obovate to nearly orbiculate with 2--6 pairs of
lateral veins, 0.5--3 × 1--2.5 cm, base cuneate to rounded,
margins dentate-crenate, teeth obtuse to rounded, apex obtuse to
rounded; surfaces abaxially glabrous to moderately pubescent,
especially along major veins and in vein axils, often covered
with resinous glands. Infructescences erect, cylindric, 1--2.5 ×
0.5--1.2 cm, shattering with fruits in fall; scales glabrous,
lobes diverging distal to middle, central lobe elongate, lateral
lobes ascending, somewhat shorter and broader than central lobe.
Samaras with wings narrower than body, broadest near summit,
extended slightl