Deciduous, dioecious trees. Bud-scales usually resinous, in several overlapping series, the outermost shortest. Leaves relatively broad, broadly elliptic to deltoid, rhombic or cordate, entire to deeply lobed; petiole relatively long (at least one-quarter as long as lamina); stipules narrow, caducous. Catkins terminal, cylindric; catkin-scales entire or laciniate; nectary obliquely cup-shaped; stamens 4–many; ovary usually flask-shaped, stigmas 2, entire or bilobed. Capsule 2–4-valved; seeds numerous, each with a basal coma of silky hairs.
30–40 species in temperate Northern Hemisphere regions, 1 in tropical Africa; 7 naturalised in Australia.
Populus has a long history of cultivation. Many of the taxa grown in Victoria are cultivated clones or hybrids, and can be highly variable. Hence the taxonomy of this genus is complicated, as is the identification of specimens. In some cases it may be necessary to observe a range of plants over all seasons before a satisfactory identification can be made.