A well known genus of deciduous trees natives of Europe, Asia and America. The genus contains about eighteen species, many of which, when given congenial soil, are among the most rapid growers of the forest. They thrive best in a deep damp soil, where the underground water is near the surface, or along the banks of creeks or watercourses.

The favorite species are the Carolina, the Lombardy (pyra-midalis), the Aspen and the Silver-leaved.

Propagate by cuttings placed in the open ground in November.