Juglans regia L. - Persian walnut.
Taxonomic position.Family Juglandaceae A. Rich. ex Kunth genus Juglans L.
Synonyms.J.fallax Dode, J. regia subsp. fallax Dode.
Morphology and biology.Deciduous tree, verdant in summer, up to 30-35 m tall, with a broad, dense crown. Young branches are downy but later become bare and smooth. Leaves are compound, pinnate, but not in pairs, consisting of 7 or sometimes 5-9 very fragrant, dark green leaflets. Fruit is false drupe, exceedingly variable in shape and size. Outer fruit coat is green, fleshy, varying in thickness, pubescent or bare. Endocarp is light brown, dark brown or sometimes gravel-colored, ligneous, with a very pitted, knobby or smooth surface, having two distinctly developed ribs. Monoecious, with diclinous flowers. Wind-pollinated. Zoochore. Propagated by seed, grafts and cuttings. Blossoms in April/May; bears fruit in August/September (early October). 2n=32.
Distribution.Occurs throughout the mountains of Middle Asia (Fergana, Chatkal, Pskem and Ugam Ranges; in Tajikistan, occurs from the Zeravshan Range in the north to the Shakhdarin Range in the south, as well as in Kopet Dagh along the Sumbar River); the Balkan Peninsula; Asia Minor; Iran; Afghanistan; and Southeastern China. Throughout most of the Caucasus, it has turned wild, yet its area of distribution as a wild plant is very limited in this region. Small groves were found in Kakhetia, Lenkoran and Abkhazia; solitary locations are in Talysh. Central Asian walnut forests are the largest in the world, about one half of them situated in the Pamir-Altai region.
Ecology.Mesophyte. Photophilous. Inhabits rich and well-moistened soils in ravines and river valleys as well as the mountainsides that face them. Grows alongside maple, ash and apple or in pure stands in the lower and middle mountain zones. The highest location of Persian walnut is reported in Tajikistan, near Lyangar village, at the altitude of 3,000 m. While being a thermophilous wood species, in the mountains of Middle Asia, some adult trees of Persian walnut endure frosts of -25°C.
Utilization and economic value.Food, oil-bearing, industrial, tanning, ornamental and medicinal plant. Edible seed is rich in oil and albumens. Walnut oil has excellent taste and is used for food as well as in oil painting, as it belongs to the group of drying oils. Foliage, bark, and, most of all, green coat of the nut is used for dyeing fabric and wood in various gradations of black and brown colors. Leaves and green fruit coats are also used in medicine. Walnut wood is dark reddish brown with a beautiful pattern, very firm and strong, easily workable and non-susceptible to worms. It is used in timbering, woodturning and in the aircraft industry.
Reference citations:Brezhnev D.D., Korovina O.N. 1981. Wild relatives of cultivated plants in the flora of the USSR. Leningrad: Kolos, 108 pp. (In Russian)
Kubli V.A. 1977. Areas of distribution of trees and shrubs in the USSR. Vol. 1. Leningrad: Nauka, pp. 87-88. (In Russian)
Smolyaninova, L.A. 1936. Juglans L.-Walnut. Cultivated flora of the USSR. Nuciferous plants. Moscow-Leningrad. 44-77 pp. (In Russian)