This is the common cottonwood of California, and of other western states, which does not appear to have been introduced to Britain previous to 1904. It is one of the black poplars with the characteristic compressed leaf-stalk of that group. Leaves broadly diamond-shaped, triangular, or somewhat kidney-shaped, 11⁄2 to 4 in. wide, usually less in length, the margin coarsely round-toothed, except at the short, abrupt point, and at the straight, broadly wedge-shaped or slightly heart-shaped base; stalk 11⁄2 to 3 in. long, and, like the young shoots and leaves, soon quite glabrous. Catkins 2 to 4 in. long. From the black poplar of eastern N. America this appears to differ in its proportionately broader leaves without glands at the base. According to Jepson it is 40 to 90 ft high in California, having a round-topped, massive head of branches. It has no particular value for the garden, and is tender in some forms.
P. wislizenii Sarg. – This differs from P. fremontii in having the stalks of the female flowers conspicuously longer; they are 1⁄2 in. long, but only 1⁄12 to 1⁄3 in. long in P. fremontii. Its habitat, in Texas, New Mexico, etc., is south and east of that of P. fremontii.