to 40 m. Winter buds
pubescent, hairs relatively short, stiff. Leaves:
blade base usually with 2 round basilaminar glands, apex long-acuminate, abaxial surface glabrous at emergence; preformed blade with (3-)7-15(-21) teeth on each side; neoformed blade lengths about equaling widths. Pedicels:
lengths uniform, 1-6(-8 in fruit) mm. Capsules
with thin, flexible valves. Flowering Mar-Jun; fruiting May-Jul. Along streams and lakes, usually in mesic soils, on dunes, also cultivated; 50-2200 m; Alta., Man., Ont., Sask.; Colo., Idaho, Ill., Ind., Iowa, Kans., Mich., Minn., Mo., Mont., Nebr., N.Mex., N.Y., N.Dak., Ohio, Okla., Oreg., Pa., S.Dak., Tex., Wash., Wis., Wyo. Subspecies monilifera
is the abundant cottonwood of the Great Plains and extends sparsely through the Rocky Mountains to the Columbia Plateau. It intergrades with subsp. deltoides
in a band along the southeastern edge of the Great Plains to the Great Lakes region. These intermediates have longer pedicels and may have 3-5 elongate basilaminar glands. It intergrades also with subsp. wislizeni
along the southwestern margin of the Great Plains, where there are plants with longer pedicels and preformed leaves with fewer teeth and without basilaminar glands.