Betulaceae -- the birch or alder family (6/120-170; mostly cool-temperate regions of Northern Hemisphere but extending southward in montane habitats to the Andes)
Habit shrubs or trees
Leaves alternate, simple, stipulate
Inflorescences both staminate (with 2-3 flowers) and pistillate (with 1-3 flowers) inflorescences as cymules subtended by scale-like bractlets in catkins: pistillate catkins not as elongate and pendulous as staminate catkins
Special floral characters flowers always imperfect and always in catkins, when the calyx fused to the extent that it is not visible, the pistillate flower is called nude and appears superior, but is actually inferior
Calyx of pistillate flowers: 2-4 (0) sepals very reduced; connate and adnate to ovary Calyx of staminate flowers: 2-4 (-6) sepals distinct
Corolla absent
Androecium 2-6 (-8) stamens, distinct or filaments basally connate
Gynoecium 2 carpels; connate; superior (appears that way in nude flowers) to inferior; 1-loculed above, 2-loculed below with 1 axile ovule/locule; 2 styles
Fruit= achene, nut or samara
(Floral formulas: Ca 2-6 A 2-20 AND G 2 OR A 2-8 AND Ca 2-6 G 2 )