T.E.R:R.A.I.N - Taranaki Educational Resource: Research, Analysis and Information Network

Populus deltoides (Eastern cottonwood)

Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Rosids
Order: Malpighiales
Family: Salicaceae
Genus: Populus
Section: Aigeiros
Species: P. deltoides
Binomial name: Populus deltoides
Synonym: Populus angulata
Common names: Eastern cottonwood, Necklace poplar, Poplar

Populus deltoides is a poplar native to Eastern North America. In New Zealand these trees have been used as a bioremediation for erosion. Populus deltoids and other broad leaved, deciduous trees are planted on pastoral land because of the binding power of their impressive root system.

Populus deltoides is a large, fast growing tree growing to >40 m tall and with a trunk > 1.8 m diametre. The bark is silvery-white, smooth or lightly fissured when young, becoming dark grey and deeply fissured on old trees. The twigs are greyish-yellow and stout, with large triangular leaf scars. The winter buds are slender, pointed, 1–2 centimetres long, yellowish brown, and resinous. 
The leaves are large, deltoid (triangular), >10 cm long and >11 cm broad with a truncated (flattened) base and a petiole 3–12 cm  long. The leaf is very coarsely toothed, the teeth are curved and gland tipped, and the petiole is flat; they are dark green in the summer and turn yellow in the autumn. Due to the flat stem of the leaf, the leaf has the tendency to shake from even the slightest breeze. This is one of the identifying characteristics.
It is dioecious, with the flowers (catkins) produced on single-sex trees in early spring. The male (pollen) catkins are reddish-purple and 8–10 cm long; the female catkins are green, 7–13 cm long at pollination, maturing 15–20 cm long with several 6-to-15-millimeter seed capsules in early summer. The capsules of this species are 3-valved, and open to release seeds that have a silky coma attached. Seeds are dispersed by wind.

Populus deltoides planted to stablilise a roadside bank.

The seed capsules.have opened releasing seeds that have a silky coma (a tuft of hairs surroundiny the tips of a seed)  

A road side covered with wind blow comas

Thanks to Wikipedia for text and information: https://creativecommons.org/licenses/by-sa/3.0/