Cottonwood leaf, Bosque del Apache National Wildlife Refuge, San Antonio NM, November 10, 2014

Before the Fall

Cottonwood Leaf, Bosque del Apache National Wildlife Refuge, San Antonio NM

November 10, 2014

Before the Fall

Cottonwood leaf; a portrait.

Rio Grande Cottonwood

Populus deltoides, the eastern cottonwood or necklace poplar, is a cottonwood poplar native to North America, growing throughout the eastern, central, and southwestern United States, the southernmost part of eastern Canada, and northeastern Mexico. It is a eudicot.

The species is divided into three subspecies or up to five varieties. The subspecies classification is as follows:

Populus deltoides subsp. deltoides, eastern cottonwood is found in southeastern Canada (the south of Ontario and Quebec) and the eastern United States (throughout, west to North Dakota to Texas).

P. d. monilifera (Aiton) Eckenw., the plains cottonwood (syn. P. deltoides var. occidentalis Rydb.; P. sargentii Dode) ranges from southcentral Canada (southern Alberta, Saskatchewan, and Manitoba) to the central United States and south to northern New Mexico and Texas.

P. d. wislizeni (S.Watson) Eckenw., the Rio Grande cottonwood (syn. P. wislizeni (S.Watson) Sarg.; P. fremontii var. wislizeni S.Watson) grows from southern Colorado south through Texas to northeastern Mexico (Chihuahua, San Luis Potosi), and west to Arizona (presence in California, listed by GRIN, is doubtful, not included in the Jepson Flora of California). (Note: Some sources mistakenly spell the epithet "wislizenii." Correct spelling is with one "i," per ICN article 60C.2.)

It needs bare soil and full sun for successful germination and establishment; in natural conditions, it usually grows near rivers, with mud banks left after floods providing ideal conditions for seedling germination; human soil cultivation has allowed it to increase its range away from such habitats.