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Juglans × intermedia Carr.

Modern name

Juglans intermedia Carrière

Synonyms

J. intermedia var. pyriformis Carr.; J. regia var. intermedia C. DC.

This is the collective name for hybrids between the common walnut, J. regia, and the black walnut, J. nigra. They have arisen in various places, both in Europe and the USA, where the two species grow together. These hybrids, at least in the first generation, have the aspect and bark of the common walnut, but the young shoots are sometimes downy, as in the black walnut. Leaves usually with five or six pairs of leaflets, slightly toothed. Fruits nearer to those of the black walnut. Carrière was not the first to identify this hybrid: a year earlier Casimir de Candolle had described one that grew at Trianon but chose to call it J. regia var. intermedia.

The most famous specimen of J. × intermedia grows in the garden of M. de Vilmorin at Verrières-le-Buisson, near Paris (J. × intermedia var. vilmoreana (Carr.) Schneid). Planted in 1816, this tree measured 80 × 712 ft in 1863, and 95 × 10 ft in 1905.



From the Supplement (Vol. V)

specimens: Nymans, Sussex, Arboretum, 95 × 614 ft (1985); Hergest Croft, Heref., 98 × 1214 ft at 3 ft (1985); Birr Castle, Co. Offaly, Eire, 50 × 3 ft (1985).

Genus

Juglans

Other species in the genus