The Willow family, to which the Osier belongs, is, like the Brambles, a difficult group even for the botanist, and he is a bold man or a very clever one who undertakes to identify specimens off-hand. They have suffered much at the hands of the “splitter.” Hooker gives the number of British species as eighteen, with a considerable number of varieties; but by Babington many of these varieties are given specific rank, and his list of species runs to fifty-eight. It would, of course, be absurd for us to attempt in this restricted space to give a key even to Hooker’s list; but our details of the flower structure, etc., will be found to apply in the main to all willows, and for a knowledge of the other species our readers must refer to Hooker. It should be added that, to increase the difficulties of the botanist, the plants that bear male flowers as a rule differ considerably from those that produce female flowers; for with scarcely an exception each plant is of one sex only.
The Osier (S. viminalis) is one of our most common species, and is the one most generally used for basket-weaving. It is a large shrub or low bushy tree, growing in wet places beside rivers and pools, or more frequently in Osier-beds. When allowed to grow uncut it attains a height of twenty or thirty feet; its long, smooth, and straight branches well furnished with very narrow leaves, tapering to a fine point, and sometimes nearly a foot in length. The margins of the leaf are quite free from teeth or lobes, and are curled back on the shining white silky underside. Both male and female flowers form catkins: the males each consisting of a hairy scale, to which are attached two stamens; the females of a similar scale bearing the ovary. The catkins appear before the leaves, in March or April. Salix is the old Latin name for Willows and Osiers.
Osier.
Salix viminalis.
—Salicineæ.—
The Lombardy Poplar (Populus fastigiata).
It is an easy step from the Willows to the Poplars, for the Genus Salix and the Genus Populus together form the Order Salicineæ. We have only two indigenous species in Britain—the White Poplar or Abele (P. alba), and the Aspen (P. tremula). In spite of the fact that it was not introduced until 1758 it may safely be said that the Lombardy Poplar is now a better known tree than either of our native species. It is the tree that is so frequently planted as a live screen, to break the force of the wind or to hide some undesirable prospect. Its growth is most rapid, and the story is told of a man who planted this tree in his garden at Great Tew, in Oxfordshire, and was living fifty years after, by which time his tree had beaten him considerably in the matter of growth, being then a hundred and twenty-five feet high! But like most other trees of rapid growth it attains no great age—for a tree, that is—and it is doubtful if it exceeds a century of life. The whole of its branches and shoots take an upward direction, which gives the tree the fastigiate or sharp-pointed outline which has suggested its specific name.
In our native Poplars the shoots are downy; in fastigiata they are smooth. The leaves are borne on long compressed stalks, which give them the ever-tremulous movement so well known in connection with the Aspen. As in the Willows, the sexes are on separate trees, and the flowers all in catkins. There is no perianth, a single bract-like scale serving instead, though there is a cup-shaped organ, within which is found, in one plant, a one-celled ovary, and in the other sex from twelve to twenty stamens with red anthers are attached to the under-side of the cup.
Lombardy Poplar.
Populus fastigiata.
—Salicineæ.—