In the September 2006 issue ofScience, it was announced that the Western Balsam Poplar (P. trichocarpa) was the first tree to have its fullDNA codesequenced.[2]
Theflowers are mostlydioecious (rarelymonoecious) and appear in early spring before the leaves. They are borne in long, droopingcatkins. The male flowers have a group of 4–60stamens on a disk. The female flower is a single-celledovary in a cup-shaped disk.
Pollination is by wind. Thefruit is a two to four-valvedcapsule, green to reddish-brown, mature in mid summer. It contains tiny light brownseeds surrounded by tufts of long, soft, white hairs which help wind dispersal.[3][4][5]
Poplars of the cottonwood section are oftenwetlands orriparian trees.[6] The aspens are among the most importantboreal broadleaf trees.[3]
Poplars and aspens are important food plants for thelarvae of a large number ofLepidoptera species.Pleurotus populinus, the aspen oystermushroom, is found exclusively on dead wood ofPopulus trees in North America.
.jpg)