BLACK POPLAR

'Black Poplar' (''Populus nigra'') is a species of poplar in the cottonwood section of the genus ''Populus'', native to Europe, southwest and central Asia, and northwest Africa.Flora Europaea: ''Populus nigra''
It is a medium-sized to large deciduous tree, reaching 20-30 m (rarely 40 m) tall, with a trunk up to 1.5 m diameter. The leaves are diamond-shaped to triangular, 5-8 cm long and 6-8 cm broad, green on both surfaces.Rushforth, K. (1999). ''Trees of Britain and Europe''. Collins ISBN 0-00-220013-9.
There are three subspecies, some botanists distinguishing a fourth:

★ ''Populus nigra'' subsp. ''nigra''. Central and eastern Europe. Leaves and shoots glabrous (hairless); bark grey-brown, thick and furrowed.

★ ''Populus nigra'' subsp. ''betulifolia'' (Pursh) W.Wettst. Northwest Europe (France, England). Leaf veins and shoots finely downy; bark grey-brown, thick and furrowed.

★ ''Populus nigra'' subsp. ''caudina'' (Ten.) Bugała. Mediterranean region, also southwest Asia if var. ''afghanica'' not distinguished.

★ ''Populus nigra'' var. ''afghanica'' Aitch. & Hemsl. (syn. ''P. nigra'' var. ''thevestina'' (Dode) Bean). Southwest Asia; treated as a cultivar of ''P. nigra'' by many botanists,Germplasm Resources Information Network: ''Populus nigra'' var. ''thevestina'' and as a distinct species ''P. afghanica'' by others;Flora of Pakistan: ''Populus afghanica'' bark smooth, nearly white; leaves and shoots as subsp. ''caudina'' (see also cultivars, below).
The subspecies ''betulifolia'' is regarded in some circles as being one of the most endangered trees in United Kingdom due to loss of habitat.^[1][2]
Several cultivars have also been selected, these being propagated readily by cuttings:

★ '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.Bean, W. J. (1980). ''Trees and Shrubs Hardy in the British Isles'' Vol. 3. John Murray ISBN 0-7195-2427-X

★ Plantierensis Group. A group of clones derived by crossing 'Italica' with ''P. nigra'' var. ''betulifolia'' at the Plantières Nursery near Metz in France in 1884; it is similar to 'Italica' (and often mistaken for it) but with a slightly broader crown, and is better adapted to the cool, humid climate of northwest Europe, where the true Lombardy Poplar does not grow well. Both male and female clones are grown. This is the tree most commonly grown in the British Isles as "Lombardy Poplar".

★ 'Manchester Poplar'. A cultivar of subsp. ''betulifolia'' widely planted in northwest England. It is a male clone, and currently seriously threatened by Poplar Scab disease.^[3][4]

★ 'Gigantea'. Another fastigiate clone, of unknown origin, with a rather broader, more vigorous crown than 'Italica'. It is a female clone.

★ 'Afghanica' (syn. 'Thevestina'). Most, if not all, specimens of the variety ''afghanica'' are of a single clone, and many botanists therefore treat it as a cultivar rather than a botanical variety. It is also fastigiate, similar to 'Italica', but with a striking whitish bark; it also differs from 'Italica' in being a female clone. This is the common fastigiate poplar in southwest Asia and southeast Europe (the Balkans), where it was introduced during the Ottoman Empire period.

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References

References

1. Milne-Redhead, E. (1990). The B.S.B.I. Black Poplar survey, 1973-88. ''Watsonia'' 18: 1-5. Available online (pdf file).
2. Arkive: ''Populus nigra''
3. Stace, C. A. (1971). The Manchester Poplar. ''Watsonia'' 8: 391-393.
4. Arboricultural Information Exchange: Manchester Poplar Disease