Native to (or naturalized in) Oregon:
- Deciduous large shrub or tree, 20-50 ft (6-15 m) tall, usually branched near the ground, broad rounded crown. Trunk bark is gray to dark brown and with age becomes deeply fissured; strongly scented. Leaves alternate, pinnately compound, 20-30 cm long, odd number of leaflets, 7-13, each leaflet narrow lanceolate, 5-7.5 cm long and 1.3-2.5 cm wide, base wedge-shaped or rounded, margin finely serrated or almost without teeth, apex long pointed, upper surface yellow-green, dull, soon becoming glabrous (without hairs), somewhat paler below; fall color is yellow. Male flowers small, each with 20 stamens, many per catkin; female flowers small, with 2 styles at branch tips. Fruit globose, 12-19 mm diameter, hairy husk becomes brown, mostly shell with a very small edible seed.
- Sun. Very heat tolerant.
- Hardy to USDA Zone 7 Native range from from southwestern Kansas through Oklahoma to central New Mexico and Texas, south into northeastern Mexico. Juglans microcarpa is morphologically similar to Juglans major, the Arizona walnut, and identification may be difficult where both species occur together (Forest Service, Fire Effects Information System).
- microcarpa: micro, from the Greek mikros, small; carpa, from karpos, fruit; a reference to the small fruit