|Populus nigra - Black Poplar|
Sub-species of Populus nigra:
* Populus nigra sub-species: nigra. Central and eastern Europe. Leaves and shoots glabrous (hairless); bark grey-brown, thick and furrowed.
* Populus nigra sub-species: 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.
* Populus nigra sub-species: caudina (Ten.) Bugała. Mediterranean region, also southwest Asia if var. afghanica not distinguished.
* Populus nigra var. sub-species: afghanica Aitch. & Hemsl. (syn. P. nigra 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.
* 'Italica'. The true Lombardy poplar, selected in Lombardy, northern Italy, in the 17th century. The growth is fastigiate, with a very narrow crown. Coming from the Mediterranean region, it is adapted to hot, dry summers and grows poorly in humid conditions, being short-lived due to fungal diseases. It is a male clone.
The green shoots soon become yellow-ochre colored, thereafter turning grey, and finally darkening. The oval winter buds are reddish and pointed and are set at uneven intervals on all sides of the twigs. The leaves are triangular to rhombic in shape, though the basal angles are rounded, not sharp. They open as khaki or light brown, but are soon deep green on top, paler under neath, with a translucent margin which bears shallow teeth. The long stalks are flattened close to the leaf-blade. The leaves turn yellow in autumn.
The attractive male catkins expand and hang like lambs’ tails in March before the leaves unfold, the anthers are crimson until they show their pale yellow pollen. The female catkins, never on the same tree as the male, are longer, with stout greenish-white stigmas. They fall in early June as numerous small down-clad capsules but they seldon contain seed. The tree is propagated by cuttings. It rarely produces suckers.
The bark is almost black, deeply and irregularly furrowed into broad, thick ridges. The wood is almost white in color, soft and light, very open in texture but with woolly fibers. It is used for packing cases, and general purposes.
Black Poplar has now been replaced for commercial planting by its quicker-growing hybrid clones, such as Populus ‘Serotina’. These are established on fertile, well-watered lowland soils to yield timber for match sticks, match boxes and baskets.