Populus nigra
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. The black poplar is a medium- to large-sized deciduous tree, reaching 20–30 m, and rarely 40 m tall. 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). Their leaves are diamond-shaped to triangular, 5–8 cm long and 6–8  cm broad, and green on both surfaces. The species is (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 quickly colonize open areas. Subspecies. Three subspecies are established and some botanists distinguish a fourth: The subspecies "P. n. betulifolia" is one of the rarest trees in Great Britain and Ireland, with only about 7,000 trees known, of which only about 600 have been confirmed  as female. Cultivars. Several cultivars have also been selected, these being propagated readily by cuttings: "Populus nigra" 'Italica' has won the Royal Horticultural Society's Award of Garden Merit. Distribution. Black poplar has a large distribution area throughout Europe and is also found in northern Africa and central and west Asia. The distribution area extends from the Mediterranean in the south to around 64° latitude in the north and from the British Isles in the west to Kazakhstan and China in the east. The distribution area also includes the Caucasus and large parts of the Middle East. Populus nigra