Section 1. Flowers in unisexual aments (_female flowers of Juglans and Quercus solitary or in spikes_); ovary inferior (_superior in Leitneriaceæ_) when calyx is present. V. SALICACEÆ. Trees or shrubs, with watery juice, alternate simple stalked deciduous leaves with stipules, soft light usually pale wood, astringent bark, scaly buds, and often stoloniferous roots. Flowers appearing in early spring usually before the leaves, solitary in the axils of the scales of unisexual aments from buds in the axils of leaves of the previous year, the male and female on different plants; perianth 0; stamens 1, 2 or many, their anthers introrse, 2-celled, the cells opening longitudinally; styles usually short or none; stigmas 2—4, often 2-lobed. Fruit a 1-celled 2—4-valved capsule, with 2—4 placentas bearing below their middle numerous ascending anatropous seeds without albumen and surrounded by tufts of long white silky hairs attached to the short stalks of the seeds and deciduous with them; embryo straight, filling the cavity of the seed; cotyledons flattened, much longer than the short radicle turned toward the minute hilum. The two genera of this family are widely scattered but most abundant in the northern hemisphere, with many species, and are often conspicuous features of vegetation. CONSPECTUS OF THE GENERA. Scales of the aments laciniate; flowers surrounded by a cup-shaped often oblique disk; stamens numerous; buds with numerous scales. 1. Populus. Scales of the aments entire; disk a minute gland-like body; stamens 1, 2 or many; buds with a single scale. 2. Salix. 1. POPULUS L. Poplar.