Populus balsamifera - Tacamahaca, or Balsam Poplar, is a very distinct species. This is particularly northern, extending to Stoneleake, lat. 634 Leaves on round petioles, dark green above, rusty brown beneath; tree of medium to large size, with open, straggling branches. Though unseemly, it is often found in cultivation.

Populus candicans, of Aiton, Balm of Gilead, is a variety called also Heart-leaved Balsam Poplar. This form is chiefly seen in cultivation, though it has little to recommend it.

Populus angustifolia, of James, is described by S. B. Watson, of Clarence King's survey of the 40th parallel, as a common tree in the Rocky Mountains. It is now grouped with candicans and balsamifera, of which it is a very distinct western form, having also quite a diversity in its foliage, some leaves being ovate, while in other trees they are nearly linear, and with a drooping spray. The resemblance to willows is very striking, as seen on the Platte river, Colorado.

*N. Amer. Sylva, vol. ii. page 120.

†New York Natural History. Botany, vol. ii. page 215.

†Dr. Torrey, Nat, Hist., N. Y. Botany, vol. II., p. 316.