Shrubs, 20-80(-150+) cm. Stems erect. Leaves mostly alternate; petioles 0; blades mostly filiform, 15-35(-65+) × 0.5-1.5 mm, sometimes with 3(-5+) filiform lobes, abaxial faces sparsely scabrellous, glabrescent, often vernicose, adaxial faces densely scabrellous (white). Pistillate heads ± intermixed with staminates; florets 1. Staminate heads: peduncles 0-0.5 mm; involucres ± cup-shaped, 1-3(-4) mm diam., ± glabrate, ± vernicose or gland-dotted; florets 5-15+. Burs: bodies plumply fusiform, 3-4(-6) mm, stipitate-glandular, wings 5-20+, ± scattered, broadly cuneiform, flabellate, or orbiculate, 3-4(-6) × 2-4(-8) mm. 2n = 36.

Flowering Mar-May(-Jun). Desert washes, sandy and gravelly benches, lava talus; 200-1800 m; Ariz., Calif., Nev., Utah; Mexico (Baja California, Sonora).

Variety salsola refers to plants bearing burs with 6-14 wings in 2-3+ cycles, their tips ± spreading to patent; var. pentalepis (Rydberg) Strother & B. G. Baldwin refers to plants bearing burs with 5-9(-13) wings in 1(-2) cycles, their tips ± spreading to patent; var. fasciculata (A. Nelson) Strother & B. G. Baldwin [= Hymenoclea salsola var. patula (A. Nelson) K. M. Peterson & W. W. Payne, an illegitimate name] refers to plants bearing burs with 10-18 wings in 2-3+ cycles, their tips antrorsely ± appressed (see K. M. Peterson and W. W. Payne 1973).

Hybrids between Ambrosia salsola and A. dumosa have been called A. ×platyspina (Seaman) Strother & B. G. Baldwin.

Wiggins 1964, Benson and Darrow 1981, Kearney and Peebles 1969

Common Name: burrobrush Duration: Perennial Nativity: Native Lifeform: Subshrub Wetland Status: UPL General: Rounded, often straggly shrub 1-2.5 m tall with stramineous bark and slender, striate, sparsely and finely pubescent branches. Leaves: Alternate, filiform, 5-35 mm long, about 0.5 mm wide, subterete, minutely pilosulous. Flowers: Staminate heads above pistillate heads or intermingled, sessile; staminate involucres 15-20 flowered, 3-4 mm wide, 5-7 rounded lobes, crenate, finely pilosulous; receptacular paleae broadly spatulate, pinnately veined; staminate corollas funnelform, puberulent; pistillate heads subtended by 1 to several linear bractlets. Fruits: Cypselae 6 mm long, with 7-12 wings in several series, beak about 2 mm long, wings reniform, narrowed to petiole-like base; sometimes in imperfect spiral. Ecology: Found along sandy washes and on rocky slopes, rarely in saline soil below 4,000 ft (1219 m); flowers March-May. Distribution: s UT, AZ, and s CA; south to nw MEX. Notes: Look for this species under Hymenoclea salsola in older literature. Spirally arranged wings can help to distinguish this species, as can its small size and rounded growth form. Ethnobotany: Unknown, other species in this genera have uses. Etymology: Hymenoclea is from hymen -membrane- and kleio -to encose, while salsola comes from the Latin salsus for salty. Synonyms: Hymenoclea salsola Editor: SBuckley, 2010