Populus nigra, the black poplar, is a species of cottonwood poplar, the type species of section Aigeiros of the genus Populus, native to Europe, southwest and central Asia, and northwest Africa.
Description
Black poplars are medium- to large-sized deciduous trees, reaching 20–30 m, and rarely 40 m tall. Their leaves are diamond-shaped to triangular, 5–8 cm long and 6–8 cm broad, and green on both surfaces. Normally, their trunks achieve up to 1.5 m in diameter, but some unusual individual trees in France have grown old enough to have much larger trunks – more than 3 metres DBH (Diameter at Breast Height).
The species is dioecious (male and female flowers are on different plants), with flowers in catkins and pollination achieved by the wind. The black poplar grows in low-lying areas of moist ground. Like most other pioneer species, the tree is characterized by rapid growth and is able to colonize open areas quickly.
Poplar seed tufts
Three subspecies are established and some botanists distinguish a fourth:
P. n. subsp. nigra. Central and eastern Europe. Leaves and shoots glabrous (hairless); bark grey-brown, thick and furrowed.
Burrs and normal bark on a black poplar tree (subspecies betulifolia) in Ayrshire, Scotland.
P. n. subsp. betulifolia (Pursh) W.Wettst. North-west Europe (France, Great Britain, Ireland). Leaf veins and shoots finely downy; bark grey-brown, thick and furrowed, often with heavy burrs, trunk usually heavily leaning.
P. n. subsp. caudina (Ten.) Bugała. Mediterranean region, also southwest Asia if var. afghanica not distinguished.
P. n. var. afghanica Aitch. & Hemsl. (syn. P. n. var. thevestina (Dode) Bean). Southwest Asia; treated as a cultivar of P. nigra by many botanists, and as a distinct species P. afghanica by others; bark smooth, nearly white; leaves and shoots as subsp. caudina (see also cultivars, below).
The subspecies P. n. betulifolia is one of the rarest trees in Great Britain...
