juglans regia, alias walnut, qiang peach. Walnuts in the family Juglanaceae are deciduous trees. The number of chromosomes 2n = 2x = 32. It is up to 30m long and has a crown width of 20 m. The bark is greyish white, the old tree is gray-brown with irregular longitudinal lobes, stout twigs, odd pinnate compound leaves, alternate, oval to inverted oval oval. Hermaphroditic heterophylla, the male flowers are soft and droopy, and the female flowers are 1 to 3 (5) in the form of a top-growing spike-like inflorescence, and the flowering period is from April to May. The drupes are spherical and ripen from September to October. Native to Xinjiang and Iran, China, Zhang Qian introduced Chinese mainland in the Han Dynasty, shaanxi, southern Liaoning, north China, northwest China more, central China, east China, south China, southwest to Tibet has cultivation. It is also found along the Mediterranean coasts of India, Central Asia, Asia Minor, Eastern Europe, and Italy. Positive trees; prefer cool climates, are more tolerant of dry and cold, and are not tolerant of heat and humidity. It prefers deep, fertile, moist, well-drained slightly acidic, neutral, weakly alkaline and calcareous soils (pH 5.5 to 8.0); salt-tolerant, drought-tolerant and waterlogged. Deeply rooted and germinating. Long lifespan. Sowing and propagation. Excellent varieties can be propagated by grafting. Common pests and diseases in cultivation include the walnut branch moth (atrijuglans hetaohei), the dyscerus juglans, the yellow thorn moth (chidocampa flavescens), the cloud-spotted sky cow (batocera horsfieldi), the grasshopper (drosich corpulenta) and the black spot (xanthomonas juglandis). Hu nucleus is a heterophyte pollinating plant, the intraspecific variation is common, germplasm resources are very rich, in the long-standing cultivation practice, cultivated many excellent varieties, including: dew kernel walnut, paper skin walnut, panicle walnut, thin shell walnut, medium shell walnut, thick shell walnut and other early and late fruiting varieties of taxa. The walnut canopy is wide and majestic, with large shade and thick leaves, with a gray and white trunk, which is very beautiful, and is a good shade tree, landscape tree and street tree, which is suitable for planting alone or in the grass in the garden. Because walnuts have a fragrant smell, their volatiles have bactericidal and insecticidal effects, and should be used as a green tree species in the health care area. The material is excellent and the nuts are edible.
Common species in this genus include j. sigillata , wild walnut ( j. cathayensis ) and j. mandshurica .