General: Smoketrees (Psorothamnus spinosus) are upright, medium-sized, spindly, many branched, thorny trees. The stems are many, straight, and stout, and each twig is tipped with a spine. Smoketrees grow in washes and often appear as a puff of gray smoke in the distance, hence the name.

Smoketrees are found in washes in the Lower Sonoran (Creosote-Bursage Flats) and Upper Sonoran (Mojave Desert Scrub) life zones, mostly to the south of Las Vegas. Look for them in the Mojave National Preserve, especially along Kelbaker Road south of Interstate 40, and in Joshua Tree National Park along the south entrance road south of Cottonwood Campground.

Family: Pea (Fabaceae).

Other Names:

Plant Form: Medium-sized, spindly, many branching tree.

Height: Usually 10-15 ft, to about 25 feet.

Trunk: Upright, many branches, gray brown.

Stems: Green, turning brown and gray with age, tipped with a spine.

Leaves: Oblanceolate, simple, to about 2 cm, gland-dotted; deciduous.

Flowers: Bloom during spring and into the summer (at least mid-August). Inflorescence is a dense raceme that grows near the spiny twig tips. Flower: typical pea flower with unequal lobes, 6–8 mm, purple; sepals with orange glands.

Seeds: Fruit: seed pod, slightly elongate, covered with orange glands.

Distribution: California, Arizona, and northern Mexico.

Elevation: Lower elevations to about 1,200 ft.

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