They are borne in long, drooping, sessile or pedunculate catkins produced from buds formed in the axils of the leaves from the previous year.

The male flowers are without calyx or corolla, and comprise a group of four to 60 stamens inserted on a disk; filaments are short and pale yellow; anthers are oblong, purple or red, introrse, and two-celled; the cells open longitudinally.

The fruit is a two- to four-valved dehiscent capsule, green to reddish-brown, mature in midsummer, containing numerous minute, light-brown seeds surrounded by tufts of long, soft, white hairs aiding wind dispersal.

Recent genetic studies have largely supported this, confirming some previously suspected reticulate evolution due to past hybridisation and introgression events between the groups.

[8] Some of the most easily identifiable fossils of this genus belongs to Poplus wilmattae, which come from the Late Paleocene of North America about 58 million years ago.

Pleurotus populinus, the aspen oyster mushroom, is found exclusively on dead wood of Populus trees in North America.

Almost all poplars take root readily from cuttings or where broken branches lie on the ground (they also often have remarkable suckering abilities, and can form huge colonies from a single original tree, such as the famous Pando forest made of thousands of Populus tremuloides clones).

Common poplar varieties are: The trees are grown from kalam or cuttings, harvested annually in January and February, and commercially available up to 15 November.

[15] Poplar continued to be used for shield construction through the Middle Ages and was renowned for a durability similar to that of oak, but with a substantial reduction in weight.

In addition to the foliage and other parts of Populus species being consumed by animals, the starchy sap layer (underneath the outer bark) is edible to humans, both raw and cooked.

In the United States, scientists studied converting short rotation coppice poplar into sugars for biofuel (e.g. ethanol) production.

[21] Considering the relative cheap price, the process of making biofuel from SRC can be economically feasible, although the conversion yield from short rotation coppice (as juvenile crops) were lower than regular mature wood.

Similarly, though typically it is considered to have a less attractive grain than the traditional sitka spruce, poplar is beginning to be targeted by some harp luthiers as a sustainable and even superior alternative for their sound boards:[23] in these cases another hardwood veneer is sometimes applied to the resonant poplar base both for cosmetic reasons, and supposedly to fine-tune the acoustic properties.

[25] This plant has been successfully used to target many types of pollutants including trace element (TEs) in soil[26] and sewage sludge,[27][28] Polychlorinated Biphenyl (PCBs),[29] Trichloroethylene (TCE),[30] Polycyclic Aromatic Hydrocarbon (PAHs).