This section is from the book "British Wild Flowers - In Their Natural Haunts Vol5-6", by A. R. Horwood. Also available from Amazon: A British Wild Flowers In Their Natural Haunts.
As with the Crack Willow there have been no traces of this tree preserved in early leaf or seed deposits. It is found in the N. Temperate Zone in Europe, N. Africa, N. and W. Asia, N.W. India. In Great Britain it does not grow in N. Devon, E. Kent, Monmouth, Glamorgan, Cardigan, Carnarvon, Flint, Derby, Mid Lancs, S. E. Yorks, Isle of Man, Kirkcudbright, Haddington, Linlithgow, Mid Perth, N. Perth, Banff, Easterness, Westerness, Mid and N. Ebudes, N. Highlands, North Isles, but generally elsewhere. It is planted in Sutherland and the Hebrides. In Ireland and the Channel Islands it is perhaps never native.
As with the Crack Willow the White Willow is a sure indication of moist conditions, and its favourite situation is by the waterside, whatever shape that may take, whether a stream, a lake, a marsh, or a bog. Hut it is also a lowland plant, and is absent from dry conditions generally.
The White Willow is less lofty than the Crack Willow, with (in proportion) a stouter stem and the branches ascending, but tapering and spreading, the twigs olive-coloured, silky, and hard. The bark is fissured. The leaves are long, lance-shaped, finely toothed, bluish below, downy or silky both sides, and glandular. The leaves are arranged in spiral whorls. The stipules, or leaflike organs, are egg-shaped, and fall. The lowest teeth are glandular.
Photo C B. Dixon - White Willow (Salix alba, L.)
The flowers are in slender lax catkins, with hairy stamens and deeply-cloven stigmas. The capsule is sessile. The scales of the catkins are linear, and not so long as the stamens. The plant is dioecious.
The tree is 80 ft. high. It flowers in April and May. It is a deciduous tree propagated by seeds.
The flowers are adapted, as in S. fragilis, to visits by insects, and are also pollinated by the wind, having been derived from such ancestors (see S. fragilis). The honey is half-concealed.
The seeds are fringed with white silky hairs, and are thus blown to a distance by aid of the wind. The hairs help to fasten the seed also when it has come to rest on the ground.
The margins of the leaves are galled by Eriophyes marginatus and Cecidomyia clausilia. A beetle, Elater sanguineus (rufipennis); several Hymenoptera, Cimbex variabilis, Nematus capreoe; Lepidop-tera, Camberwell Beauty (Vanessa antiopa), Red-tipped Clearwing (Trochilum formicoeformis), Striped Twin-spot Carpet (Cidaria sali-cata); several Homoptera, Idioceris adustus, I. cupreus, I. herrichii, visit it.
The second Latin name refers to the white colour of the tree, due to the pubescence of the leaves. This tree is called Duck Willow and White Willow.
It is used for fencing-poles, crates, fuel, being pollarded like the Crack Willow, and the bark is used for tanning.
Essential Specific Characters: 285. Salix alba, L. - Tree, spreading, twigs pliable, leaves lanceolate, silky both sides, catkins lax, erect, capsule subsessile.