Populus nigra L.
Eng.: Black-poplar. Spa.: Chopo, álamo negro. Fre.: Peuplier noir, peuplier comun. Ara.: Safsaf, al haur, blinz. Tam.: Acafsaf, arig, erg, uisd.
Deciduous tree, dioecious, up to 30 m in height, ± regular in shape; crown ovoid (cylindrical in some cultivated forms) with extended branches. Trunk straight up to 1.5 m in diameter, with a grey to blackish bark and highly fissured longitudinally from young; sometimes with the surface covered in numerous lumps and a large amount of regrowths born almost from the base. Branches glabrescent, first yellow and turning greenish-grey to light brown over the years. Buds with 4-6 scales, usually quite viscous, glabrescent. Leaves alternate, 4-10 × 4-8 cm, all similar in shape, ovate-rhomboid or ovate-triangular more often, the base a wide wedge, with crenate-dentate margin, resinous and sometimes somewhat pubescent at birth, then they quickly lose this viscosity and become glabrous, ± dark green on the upper side and slightly lighter green on the underside; long petioles. Flowers in cylindrical pendant aments, male aments 3-9 × 0.8-1.5 cm, sessile, slightly hairy; female aments 7-15 × 0,6-0,9 cm, with short peduncle. Flowers with persistent nectariferous disk; male flowers with 6-25(30) stamens with white filaments and purple anthers; female flowers with ovoid-conical ovary and 2 yellow stigmas. Fruit a small ellipsoid capsule about 8 mm, dehiscent into 2 valves that release numerous minute seeds, with long whitish hairs. These hairs (joined to the seeds) fall after remaining suspended in the air for some time, accumulating on the floor in characteristic cottony masses. 2n = 38.
Flowering:
February to March.
Fruiting:
April to May.
Habitat:
In areas of high edaphic humidity, usually along rivers, streams, lake and wetlands margins, in temperate climates.
Distribution:
This species is present throughout most of Eurasia; scattered across the region. However, the origin of many specimens and even populations is doubtful because this tree has been widely cultivated since ancient times. Some authors believe that it is not an indigenous species in North Africa despite its wide distribution, where it is found over almost the entire Mediterranean region (Morocco, Algeria, Tunisia and Libya). Other subspecies, varieties and hybrids, clearly introduced, have frequently been cultivated.
Observations:
According some authors in eastern Europe (Italian and Balkan peninsulas) and in North Africa, indigenous populations of this tree correspond to the subsp. neapolitana (Ten.) Maire (P. neapolitana Ten.), but its status is doubtful.
Conservation status:
Relatively common and widespread species. It is not considered threatened. It is listed at a global level in the IUCN Red List of Threatened Species as Least Concern (LC) (Participants of the FFI/IUCN SSC 2006).