I L W I L 589 Some pollen must also be transported by the wind to the female flowers. The tuft of hairs at the base of the seed doubtless facilitates rapid dispersion of the seed, early germination of which is rendered desirable owing to its tenuity and the absence of any perisperm. Although the limitations of the genus are well marked, and its recogni tion in consequence easy, it is otherwise with regard to the species. The greatest difference of opinion exists among botanists as to their number and the bounds to be assigned to each. The cross-fertilization that takes place between the species of course intensifies the difficulty. Andersson, a Swede, spent nearly a quarter of a century in their investigation, and ultimately published a monograph which is the standard authority on the subject. He admits about a hundred species. Some botanists have enumerated eighty species from Great Britain alone, while others count only a dozen or fifteen. To illustrate the great perplexity surrounding the subject, we may mention that to one species, S. niyricans, one hundred and twenty synonyms 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 differences of opinion prevail. Andersson says that he has rarely seen two speci mens 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 varia tion in so-called species, so that the attempt to define the indefinable can at best result only in an arbitrary grouping. Few genera have greater claims to notice from an economic point of view. As timber trees many of the species are valuable from their rapidity of growth and for the production of light durable wood, serviceable for many purposes. Among the best trees of this kind are S. fragilis, especially the variety known as S. fragilis, var. Russelliana, and 3. alba, the white or Huntingdon willow. These trees are usually found growing by rivers banks or in other moist situations, and are generally pollarded for the purpose of securing a crop of straight poles. This plan is, however, objection able, as inducing decay in the centre of the trunk. Where poles arc required, it is better to treat the trees as coppice and to cut the trunk level with the soil. S. Capriea, 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 charcoal. Its catkins are collected in England in celebration of Palm Sunday, the gaily-coloured flowers being available in early spring when other decorations of the kind are scarce. Certain sorts of willow are largely used for basket-making and wicker-work. The specit S employed for this purpose are mostly of shrubby habit, and are known under the collective name of osiers. The best for planting, according to Mr Scaling, is the bitter osier, S. purpiirca ; planted on rich, well-drained soil, subject to occasional 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 green osiers, suitable for hoops and valuable for retaining the soil on sloping embank ments. S. ritellina yields the yellow osiers. Osiers are largely imported into England from Belgium and France, but might with advantage be much more abundantly grown in the United King dom than they are. They are easily propagated by truncheons or cuttings, inserted in a slanting direction into the soil for a depth of 8 to 10 inches. Mr Scaling recommends that they be planted 18 inches apart, thus employing about 20,000 cuttings per acre, the whole cost of planting being estimated ait 25 the acre. A crop is obtained the third year after planting, and one may be expected annually for the succeeding ten years. The average yield is cited at 6 to 7i tons, ranging in price from 2, 10s. to 3, 10s. a ton (unpceled). Land unsuitable for root or grain crops can be utilized for the growth of osiers ; but, as in the case of all other plants, good cultivation, including the selection of sorts appropriate to the locality, drainage, manure, &c., ensures the best return. S. acumi- nata and other species do well by the seaside, and are serviceable as wind-screens, nurse-trees, and hedges. S. daphnoidcs, .9. rep fit ft, and other dwarf kinds are useful for binding heathy or sandy soil. In addition to their use for timber or basket-making, willows COTI- tain a large quantity of tannin in their bark. A bitter principle named SALICIN (q.v.) is also extracted from the bark. As orna mental trees some willows also take a high 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 China, the willow of the Euphrates (Ps. cxxxvii. ) being in all probability Populus euphratica. S. babylonica is sometimes spoken of as Pope s willow, having been cultivated by that poet, of as Napoleon s willow, because his tomb at St Helena is overshadowed by a tree of this species, from which many offsets exist or are reputed to exist in modern gardens. S. rcgalis has very white, silvery leaves. S. rosmarinifolia is remarkable for its very narrow leaves, purplish above, silvery beneath. WILLUGHBY, FKANCIS (1(535-1672), English orni thologist and ichthyologist, who is memorable as the pupil, friend, and patron as well as the active and original co- worker of John RAY (q.v.), and hence to be reckoned as one of the most important precursors of Linnaeus. He was the son of Sir Francis Willughby, and was born in 1635. His connexion with Ray dated from his studies at Cambridge (1653-59); and, after concluding his academic life by a brief sojourn at Oxford, and acquiring consider able experience of travel in England, he made an exten sive Continental tour in his company. The specimens, figures, and notes thus accumulated were in great part elaborated on his return into his Ornithologia, which, how ever, he did not live to publish, having injured a naturally delicate constitution by alternate exposure and over-study. This work was published in 1676, and translated by Ray as the Ornithology of Fr. Willughby (London, 1678, fol.) ; the same friend published his Historia Piscium (1686, fol.). Willughby died on 3d July 1672. In Ray s preface to the former work he gives Willughby much of the credit usually assigned to himself, both as critic and system- atist. Thus, while founding on Gesner and Aldrovandus, he omitted their irrelevancies, being careful to exclude "hieroglyphics, emblems, morals, fables, presages, or ought else pertaining to divinity, ethics, grammar, or any sort of humane learning, and present him [the reader] with what properly belongs only to natural history." Again, he not only devised artificial keys to his species and genera, but, " that he might clear up all these obscurities [of former writers] and render the knowledge and distinction of species facile to all that should come after, he bent his endeavours mainly to find out certain characteristic notes of each kind," while finally, in apologizing for his engravings, he yet not unjustly claims that "they are best and truest of any hitherto graven in brass." See further ORNITHOLOGY, vol. xviii. p. 4. WILMINGTON, the largest city of the State of Dela ware, L T nited States, and the county seat of New Castle county, is situated between Brandywine and Christiana creeks and on the Delaware river. The site is low, but with sufficient slope to afford suitable drainage. The surrounding country is fertile and well cultivated. Wil mington is a railway centre of considerable importance, being entered by the Philadelphia, Wilmington, and Balti more, the Baltimore and Ohio, and the Wilmington and Nojrthern Railways. The Brandywine and Christiana creeks are navigable for large vessels. The city is laid out quite regularly. The population, which in 1870 was 30,841, in 1880 was 42,478. The manufactures in 1880 gave occupation to 7852 persons, the principal branches being the manufacture of paper, iron and steel, shipbuild ing, and the making of waggons and carriages, steam- engines, bricks, morocco leather, glass, cotton, gunpowder and other explosives, matches, and flour. Wilmington was settled by Swedes in 1638. The settlement was conquered by the Dutch, who in turn handed it over to the English. It was chartered as a city in 1832, and since the middle of the century has grown rapidly. WILMINGTON, the county seat of New Hanover county, North Carolina, United States, the principal sea port and the largest city of the State, is situated on the east bank of Cape Fear river, 30 miles from the ocean. It has railroad communication to the north, south, and west, and this, together with its maritime position, makes it an important shipping point. The principal objects of trade are lumber (southern pine), naval stores, and cotton. The
manufactures include fertilizers, creosote, and carpets