The walnut genus (Juglans) plants belong to the angiosperm phylum Dicotyledonaceae (Juglandaceae). The book Chinese Walnuts (1992) describes that there are eight species of walnut in three groups in China, namely

Walnut group: Walnut (J.regia L.)

Iron Walnut (J.sigillata Dode)

Walnut Rowan group: Walnut Rowan (J.mandshurica Max.)

Hebei Walnut (J.hoperiensis Hu)

Hebei Walnut ( J.hoperiensis Hu)

Wild walnut (J.cathayensis Dode)

Heart-shaped walnut (Ji walnut) (J.cordiformis Max.)

Jibbo walnut (ghost walnut) (J.sieboldiana Max.)

Black walnut group: black walnut (J. nigra L.)

Expanded Information:

Morphological features of walnut:

Generally up to 3-5 meters high, the bark is grayish-white, shallowly longitudinally fissured, the pith of the branches lamellar, and the apex of the young branches finely pilose.

There are also up to 20-25 meters high, the trunk is shorter than other species, the crown is broad. The bark is gray-green when young, gray-white and longitudinally lobed when old. Branchlets glabrous, glossy, peltate glandular, gray-green, later brownish.

Pinnately compound leaves 25 to 50 cm long, with 5 to 9 leaflets, rarely 13. Elliptic-ovate to elliptic, terminal leaflet usually larger, 5 to 15 centimeters long, 3 to 6 centimeters wide, apex acute or acuminate, base rounded or cuneate, sometimes heart-shaped.

Entirely or with inconspicuous obtuse teeth, surface dark green, glabrous, abaxially only vein axils with microhairs, petiolules very short or absent, some shells hard, some softer

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