JUGLANS NIGRA, Black Walnut
- Juglans nigra, Linnæus, Sp. Pl. 997 (1753); Loudon, Arb. et Frut. Brit. iii. 1435 (1838); Sargent, Silva N. America, vii. 121, tt. 333, 334 (1895), and Manual Trees N. America, 128 (1905).
A tree attaining 150 feet in height, with a girth of about 15 to 20 feet, forming in the forest a narrow round-topped head, but with spreading branches when isolated. Bark of old trees dark brown, deeply furrowed with broad ridges, which are scaly on the surface.
Leaves up to 3 feet in length, of fifteen to twenty-three leaflets, which are ovate or ovate-lanceolate, long-acuminate at the apex, rounded at the base, sub-sessile, with coarse sharp irregular serrations ; upper surface with a very minute and very scattered pubescence ; lower surface with numerous glandular and simple hairs. Rachis with yellow glands and scattered glandular hairs. Young shoots with sessile yellow glands and numerous glandular hairs; older shoots pubescent. Leaf-scars obcordate, deeply notched at the apex, without any band of pubescence on their upper edge.
Staminate catkins three to five inches long; scales with six orbicular concave pubescent lobes, and a bract ¼ inch long, which is triangular and tomentose ; stamens twenty to thirty. Pistillate flowers, two to five in a spike; involucre laciniate in margin or reduced to an obscure ring below the apex of the ovary; perianth lobes ovate, acute.
Fruit solitary or in pairs,’ globose or slightly pear-shaped, pubescent, not viscid, yellowish green, 1½ to 2 inches in diameter; nut oval or oblong, 1⅛ to 1½ inch, deeply ridged irregularly, four-celled interiorly at the base, and slightly two-celled at the apex.”
Identification
In summer it is readily distinguishable from J. cinerea and the Eastern Asiatic species, which have serrate leaflets, by the character of the leaf-scar, which is deeply notched at the apex and without the transverse band above its upper margin, which characterises those species. The long acuminate pubescent leaflets distinguish it from the hybrids pyriformis and Vilmoriniana. It has much larger leaflets than J. rupestris, and cannot be confused with J. stenocarpa, which has a broadly obovate terminal leaflet.
In winter the following characters are available :—Twigs stout, reddish brown, glandular-pubescent ; lenticels small. Leaf-scars on prominent pulvini, obcordate, deeply notched above, without pubescent band, with three groups of bundle-dots. Pith large, buff-coloured, with wide open chambers. Terminal bud ovoid or conical, grey-tomentose,
A tree at Albury, Surrey, has, however, borne fruit in clusters of three, four, and six, of which specimens are preserved at Kew.
For a detailed account of the fruit, seed, and cotyledons of the species, see Lubbock, Seedlings, ii, 517 (1902).
