* Male and female catkins on short leafy shoots.
S. pentandra: small tree; leaves thick, smooth, shining, deciduous, broadly lanceolate or ovate, pointed, finely toothed; catkins cylindrical, loose; stamens about five, sometimes more. - Bay Willow. - River-sides. Fl. May, June.
S. fragilis: tree; leaves deciduous, ovate-lanceolate, pointed, smooth, serrated throughout; catkins long, loose; flowers large; stamens two; capsules stalked. - Crack Willow. - Marshy ground. Fl. April, May.
S. alba: tree; leaves deciduous, ashy-grey, silky on both sides, elliptic-lanceolate, pointed, serrated; catkins loose, cylindrical; stamens two; capsules nearly sessile. - Moist woods. Fl. May.
S. triandra: small tree; leaves deciduous, linear-oblong, serrated, smooth, paler beneath; catkins cylindrical, loose; stamens three. - Wet woods and hedges. Fl. May, and often again in August.
** Male catkins sessile, females sessile or on very short peduncles, with or without leafy bracts.
S. purpurea: shrub ; leaves deciduous, lanceolate or oblong-lanceolate, broader upwards, serrated, smooth, whitish beneath, sometimes opposite; catkins narrow cylindrical, closely packed; stamens one under each scale, consisting of an entire filament with double anther, or a forked filament with an anther on each branch. There are several allied forms. - Marshes and river-banks. Fl. March, April.
S. viminalis : shrub or small tree; leaves deciduous, linear, inclining to lanceolate, elongated, taper-pointed, entire, wavy, white and silky beneath; catkins cylindrical; stamens two, distinct. - Common Osier. - Marshy places. Fl. April, May.
S. Caprea : shrub or small tree; leaves deciduous, roundish-ovate, serrated, wrinkled, finely toothed, glaucous and downy beneath; catkins cylindrical; stamens two, distinct. - Common Sallow. - Woods and hedges. Fl. April.
S. repens : dwarf creeping shrub; leaves deciduous, small, ovate-oblong or lanceolate, nearly entire, glaucous and silky beneath; catkins short, cylindrical; stamens two, distinct.- There are several varieties. - Heaths, moors, and sandy wastes. Fl. May.