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WILLOW (Salix)

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Originally appearing in Volume V28, Page 689 of the 1911 Encyclopedia Britannica.
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WILLOW (Salix) , a very well-marked genus of See also:plants constituting, with the See also:poplar (Populus), the See also:order Salicaceae. Willows are trees or shrubs, varying in stature from a few inches, like the small See also:British S. Iterbacea and See also:arctic See also:species generally, to See also:loo ft., and occurring most abundantly in See also:cold or temperate climates in both hemispheres, and generally in moist situations; a few species occur in the tropical and sub-tropical portions of the three See also:great continents. Their leaves are See also:deciduous, alternate, See also:simple, and generally much longer than broad, whence the See also:term willow-leaved has become proverbial. At their See also:base they are provided with stipules, which are also modified to See also:form the scales investing the See also:winter buds. The See also:flowers are See also:borne in catkins (fig. 1), which are on one See also:tree male (staminate) only, on another See also:female (pistillate). Each male See also:flower consists of a small See also:scale or bract, in the axil of which are usually two, sometimes three, rarely five stamens, and still more rarely a larger number. In•addition there is a. small glandular disk, which assumes different shapes in I, 2, 4 reduced; 3, 5-7 enlarged. different species. The female flowers are equally simple, consisting of a bract, from whose axil arises usually a very See also:short stalk, surmounted by two carpels adherent one to the other for their whole length, except that the upper ends of the styles are separated into two stigmas. When ripe the two carpels See also:separate in the form of two valves and liberate a large number of seeds, each provided at the base with a tuft of silky hairs, and containing a straight embryo without any investing albumen.

The flowers appear generally before the leaves and are thus rendered more conspicuous, while passage of See also:

pollen by the See also:wind is facilitated. Fertilization is effected by See also:insects, especially by bees, which are directed in their See also:search by the See also:colour and fragrance of the 1, See also:Leaf shoot. 4, Female catkin. 2, Branchlet bearing male See also:cat- 5, Female flower. kins. 6, See also:Capsule, opened. 3, Male flower. 7, See also:Seed. (7) (6) (5) FIG. 1.—Salix caprea—See also:Common Sallow or See also:Goat Willow. si, - flowers; but some pollen must also be transported by the wind to the female flowers, especially in arctic species which, in spite of the poverty of See also:insect See also:life, set abundant See also:fruit. The tuft of hairs at the base facilitates rapid See also:dispersion of the seed, See also:early germination of which is rendered desirable owing to its tenuity.

Although the limitations of the genus are well marked, and its recognifion in consequence easy, it is otherwise with regard to the species. The greatest difference of See also:

opinion exists among botanists as to their number and the See also:bounds to be assigned to each; and the See also:cross-fertilization that takes See also:place between the species intensifies the difficulty. Andersson, a Swede, spent nearly a See also:quarter of a See also:century in their investigation, and ultimately published a monograph which is the See also:standard authority on the subject. He admits about a See also:hundred species. See also:Professor C. S. See also:Sargent (See also:Silva of See also:North See also:America) suggests 16o to 170 as the number of distinguishable species. Some botanists have enumerated 8o species from Great See also:Britain alone, while others See also:count only 12 or 15. Dr See also:Buchanan See also:White, who made a See also:special study of the British willows, grouped them under 17 species with numerous varieties and hybrids. To illustrate the great perplexity surrounding the subject, we may mention that to one species, S. nigricans, one hundred and twenty synonyms 4, Female flower with and with-out bract. 5, Single fruit from which the hairy seeds are escaping; one seed shown separately. A, B, 1, 2, about See also:half nat. See also:size, 3-5 enlarged.

have been attached. Some of these are doubtless such as no botanist, with adequate material for forming an opinion, would accept; but, after making the necessary deductions for actual mistakes and misstatements, there still remains a large number upon which legitimate See also:

differences of opinion prevail. Andersson says that he has rarely seen two specimens of this species which were alike in the collective characters offered by the stature, foliage and catkins. No better example could be found of the almost limitless variation in so-called species. Few genera have greater claims to See also:notice from an economic point of view. As See also:timber trees many of the species are valuable from their rapidity of growth and for the See also:production of See also:light durable See also:wood, serviceable for many purposes. Among the best trees of this See also:kind are S. fragilis, the crack willow (fig. 2), especially the variety known as S. fragilis. See also:var. Russelliana, and S. See also:alba, the white or See also:Huntingdon willow. These trees are usually found growing by See also:rivers' See also:banks or in other moist situations, and are generally pollarded for the purpose of securing a See also:crop of straight poles. This See also:plan is, however, objectionable, as inducing decay in the centre of the See also:trunk. Where poles are required, it is better to treat the trees as See also:coppice and to cut the trunk level with the See also:soil.

The wood of S. fragilis is used for See also:

cricket-bats; there is a great difference in the value for this purpose of timber from different soils; and wood of the female tree is said to be preferable to that of the male, S. caprea (fig. I). a hedgerow tree, generally grows in drier situations. It is a useful timber tree, and its wood, like that of S. alba, is prized in the manufacture of See also:charcoal. Its catkins are collected in See also:England in celebration of See also:Palm See also:Sunday, the See also:bright-coloured flowers being available in early See also:spring when other decorations of the kind are scarce. Certain sorts of willow are largely used for See also:basket-making and wicker-See also:work. The species employed for this purpose are mostly of shrubby See also:habit, and are known under the collective name of osiers (see BASKET, and See also:OSIER). The best for planting is the See also:bitter osier, S. purpurea; planted on See also:rich, well-drained soil, subject to occasional See also:immersion, this willow may be grown profitably for basket-work. It is also well adapted for forming wind-breaks or screens, or for holding the banks of streams and preventing the removal of the soil by the current. S. viminalis is one of the best of the See also:green osiers, suitable for hoops and valuable for retaining the soil on sloping embankments. S. vitellina yield's the yellow osiers. S. See also:acuminate and other species do well by the seaside, and are serviceable as wind-screens, See also:nurse-trees and hedges. S. daphnoides, S. repens and other See also:dwarf kinds are useful for binding heathy or sandy soil.

In addition to their use for timber or basket-making, willows contain a large quantity of See also:

tannin in their bark. A valuable medicinal See also:glucoside named ealicin (q.v.) is also extracted from the bark. The wood, especially of S. alba. is used for See also:paper pulp. As ornamental trees some willows also take a high See also:rank. The white willow is a great favourite, while the drooping habit of the weeping willow renders it very attractive. Though named S. babylonica, it is really a native of See also:China, from which it has been widely spread by See also:man; the willow of the See also:Euphrates (Ps. exxxvii.) is in all See also:probability Populus euphratica. S. babylonica is sometimes spoken of as See also:Pope's willow, having been cultivated by that poet, or as See also:Napoleon's willow, because his See also:tomb at St See also:Helena is overshadowed by a tree of this species, from which many offsets exist or are reputed to exist in See also:modern gardens. S. regalis has very white, silvery leaves. S. rosmarinifolia is remarkable for its very narrow leaves—purplish above, silvery beneath. The larvae of several nocturnal See also:Lepidoptera•feed upon the leaves of the willows, and the trunk of the sallow is often injured by the perforations of the lunar hornet See also:sphinx (Trochilium crabroniforme). WILLOW-See also:HERB, in See also:botany, the popular name for the species of Epilobium, a genus of often tall herbaceous plants, several of which are natives of Britain. The slender stems See also:bear narrow leaves and See also:pink or See also:purple flowers, which in the See also:rose-See also:bay (E. angustifolium), found by moist See also:river-sides and in copses, are 1 in. in See also:diameter and form showy spikes.

E. hirsutum, found by sides of ditches and rivers, a tall plant with many large rose-purple flowers, is known popularly as codlins-and-cream.

End of Article: WILLOW (Salix)

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