262 The Trees of Great Britain and Ireland 



JUGLANS NIGRA, Black Walnut 



Jiig/aiis nigra, Linnreus, Sj^. PI. 997 (1753); Loudon, Ark et Fruf. 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 \ 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, \\ to 2 inches in diameter; nut oval or oblong, i\ to i^ inch, 

 deeply ridged irregularly, four-celled interiorly at the base, and slightly two-celled at 

 the apex." 



iDENTIFICAXrON 



In summer it is readily distinguishable from/, cincrea 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 Vilnwriniana. It has much larger leaflets than 

 /. rupestns, and cannot be confused with / 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- 



> A Iree^at Allnuy, Surrey, has, liowever, borne fruit in clusters of three, four, and six, of which specimens are 

 preserve! nt Kew. 



- For a .letaile.l account uf the fruit, seed, aud cotyledons of the species, see Lubbock, Siedlinyi, ii. 5,7 (,902). 



