Juglans major – Arizona Walnut
Scientific Name: Juglans major
Synonyms: Juglans elaeopyren, J. microcarpa var. major, J. rupestris var. major
Common Names: Arizona Walnut, Arizona Black Walnut, New Mexico Walnut
Duration: Perennial, Deciduous
Growth Habit: Tree
Arizona Native Status: Native
Habitat: Upland, Riparian. This plant grows in rocky upland canyons and along streams from upper elevation desert areas to the mountains.
Flower Color: Inconspicuous (green female flowers and brownish yellow male flowers)
Flowering Season: Spring
Height: Up to 50 feet (15 m) tall or sometimes more
Description: The plants are monoecious with separate male and female flowers on the same plant. The yellowish staminate (male) flowers are in drooping, brownish catkins, while the light green pistillate (female) flowers are in erect, green catkins. The female flowers are followed by rounded, up to 1 1/2 inch (3.8 cm) in diameter walnuts (seeds) with a thin, fuzzy, green aging to brown outer husk and a thick, hard, woody, longitudinally grooved, brown shell containing a fleshy, oily, 2-lobed cotyledon (the nut meat). The leaves are alternate and odd-pinnately compound with 9 to 15 yellowish green above, light green below, serrate, lance-shaped, point-tipped, slightly curved leaflets with yellowish veins. The new growth is covered with velvety, rust-colored hairs. The bark is gray to brownish in color and becomes rough and deeply furrowed on older trees. The trees have a round-headed form with a spreading crown and are slow-growing and long-lived. Their mature size is determined by availability of moisture, and they are largest in riparian areas with a good supply of available water.
This is the only Juglans species found here in Arizona.
Allergenic – The flower pollen is a severe allergen.
Edible – The shelled nuts contain small but edible nut meats (walnuts) that were eaten by Native Americans. The walnuts ripen sometime from midsummer to fall.
Kingdom: Plantae – Plants
Subkingdom: Tracheobionta – Vascular plants
Superdivision: Spermatophyta – Seed plants
Division: Magnoliophyta – Flowering plants
Class: Magnoliopsida – Dicotyledons
Family: Juglandaceae – Walnut family
Genus: Juglans L. – walnut
Species: Juglans major (Torr.) A. Heller – Arizona walnut
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