Plate XXI.—Salix nigra.
| 1. Winter buds. |
| 2. Branch with sterile catkins. |
| 3. Sterile flower, side view. |
| 4. Sterile flower, front view. |
| 5. Branch with fertile catkins. |
| 6. Fertile flower, side view. |
| 7. Fertile flower, front view. |
| 8. Fruiting branch. |
| 9. Fruit enlarged. |
Salix fragilis and Salix alba.
The fragilis and alba group of genus Salix gives rise to puzzling questions of determination and nomenclature. Pure fragilis and pure alba are perfectly distinct plants, fragilis occasional, locally rather common, and alba rather rare within the limits of the United States. Each species has varieties; the two species hybridize with each other and with native species, and the hybrids themselves have varietal forms. This group affords a tempting field for the manufacture of species and varieties, about most of which so little is known that any attempt to assign a definite range would be necessarily imperfect and misleading. The range as given below in either species simply points out the limits within which any one of the various forms of that species appears to be spontaneous.
Salix fragilis, L.
Crack Willow. Brittle Willow.
Habitat and Range.—In low land and along river banks. Indigenous in southwestern Asia, and in Europe where it is extensively cultivated; introduced into America probably from England for use in basket-making, and planted at a very early date in many of the colonial towns; now extensively cultivated, and often spontaneous in wet places and along river banks, throughout New England and as far south as Delaware.
Habit.—Tree often of great size; attaining a maximum height of 60-90 feet; head open, wide-spreading; branches except the lowest rising at a broad angle; branchlets reddish or yellowish green, smooth and polished, very brittle at the base. In 1890 there was standing upon the Groome estate, Humphreys Street, Dorchester, Mass., a willow of this species about 60 feet high, 28 feet 2 inches in girth five feet from the ground, with a spread of 110 feet (Typical Elms and other Trees of Massachusetts, p. 85).
Bark.—Bark of the trunk gray, smooth in young trees, in old trees very rough, irregularly ridged, sometimes cleaving off in large plates.