The Black Italian Poplar (Populus monilifera) is another misnamed tree, for it is a native of North America, though introduced to England from the Continent in 1772 by Dr. John Hope. It has the distinction of being considered the most rapid-growing even of the Poplars. Loudon gives its rate of growth in the neighbourhood of London as between thirty and forty feet in seven years! Even in Scotland (where it has been largely planted as a substitute for Larch, since the partial failure of that tree) it attains a height of 120 feet in sixty years, when planted along the river banks. It is probably only a variety of P. nigra, which it resembles in most points, but is larger, and of very erect growth.
The Tacamahac or Balsam Poplar (Populus balsamifera) is another importation from North America, introduced in 1692. In its native country it grows to a height of eighty feet, but here forty or fifty feet is more usual. Its leaves are of more slender form than those of the other Poplars, egg-shaped, with a near approach to being lance-shaped. Their edges are toothed, their upper surface dark green and smooth, the underside whitish with cotton. The distinctive character of the tree is the fragrance of its foliage, which scents the air on moist evenings, and makes the Tacamahac a desirable tree to plant near the water, where alone it attains any moderate size.
The Willows (Salix).
There is not in the whole of the British flora another genus of plants that presents such difficulties of identification as the genus Salix. Even so hardened a botanist as Sir J. D. Hooker, in reviewing the tangle of species, varieties (natural and cultivated), and hybrids, is so far stirred from his ordinary composure that he stigmatizes it as a "troublesome genus." When Sir Joseph chose that mild adjective he was at Kew surrounded by the national herbaria and with nicely labelled living plants at hand
for comparison. What, then, can the rambling nature-lover hope to do with the Willows he comes across one at a time, without much chance of comparing? He must be content to follow the "lumpers," who group a number of these uncertain forms under the name of a species to which they have evident relationship. When he has mastered the distinctions between these aggregate species, it will be early enough to attempt the segregation of the forms and varieties under each.
In their natural condition Willows are graceful and picturesque, but a large number of the examples met with in our rambles have been so altered for commercial reasons as to be more grotesque than beautiful. It is not the timber-man who is responsible this time, for a pollard Willow, though it produces a shock-head of long slender shoots, suitable for basket-rods, lets in moisture at the top of the bole, and the wood is more or less decayed and worthless. Only four of our native Willows can be regarded as timber trees. These are the White Willow, the Crack Willow, the Bedford Willow, and the Sallow. Like the Poplars, their growth is very rapid, and their wood is consequently light, but it has the advantage of Poplar-wood in being tougher, and therefore serving for purposes where Poplar is of no value. In the present day the growers of straight-boled Willows find their best market among the makers of cricket-bats. A good deal of it is also cut into thin strips for plaiting into chip-hats and hand-baskets. The Osier is grown in extensive riverside beds for the production of long pliant shoots for the basket-weavers; though many of the so-called Osier-rods are really stool-shoots from Willows that have been pollarded, or whose leading shoot has never been allowed to grow. On those parts of our coast where the crab and lobster fishery is pursued, a regular supply of such shoots for weaving into "pots" and "hullies" is a necessity, and a "withy bed" will usually be found on some valley stream near, or on a damp terrace halfway up the cliffs.