The Fremont Cottonwood Populus fremontii occurs in California east to Utah and Arizona and south into northwest Mexico; it is similar to Eastern Cottonwood, differing mainly in the leaves having fewer, larger serrations on the edge, and small differences in the flower and seed pod structure.
The Common North American Cottonwood Species
alternate, triangular, coarsely curved teeth, Leafstalks flattened.
Bark: yellowish green and smooth.
Flowers: catkins, male - female on separate trees.