Shrubs, 100-400 cm (much branched, broomlike). Stems erect, striate, sharply angled, green distally, glabrous, resinous. Leaves cauline (proximal withered and/or sparse at flowering); sessile; blades (1-nerved) linear-lanceolate, 5-15 × 1-2 mm, reduced to scales distally, thick, bases narrowed, margins entire (often revolute), apices acute, faces glabrous, minutely gland-dotted, resinous . Heads borne singly (on nearly leafless branches) or (laterally on branchlets) in dense paniculiform arrays. Involucres cylindric to hemispheric; staminate 4-5.2 mm, pistillate 3-8 mm. Phyllaries ovate to lanceolate, 1-5 mm, margins yellowish, slightly scarious, medians green to yellow, apices rounded to acute (greenish, abaxial faces glabrous, resinous). Staminate florets 18-35; corollas 4.2-5 mm. Pistillate florets 19-31; corollas 2.5-3.5 mm. Cypselae 2-2.6 mm, finely 8-10-nerved, glabrous; pappi 7-12 mm. 2n = 18. Flowering Aug-Nov. Gravelly and sandy washes, roadsides, railroads, mesquite flats, chaparral; 50-1500 m; Ariz., Calif., N.Mex., Tex.; Mexico (Baja California, Baja California Sur, Sinaloa, Sonora). Baccharis sarothroides is recognized by its broomlike habit, narrow, sharply angular, nearly leafless, green stems, soon-withering proximal leaves, scalelike distal leaves, and heads often terminal on long branches. Specimens from California have smaller heads that sometimes are arranged laterally along the stems.

Plant: Dioecious shrub to 3 m, glabrous, sticky; stems: branches dense, erect, often leafless at flower Leaves: usually leafless and broom-like; herbage often viscid INFLORESCENCE: primary inflorescence a head, each resembling a flower; heads in a panicle; involucre cylindric to hemispheric, of staminate heads 4.2-5.2 mm, of pistillate heads 5.3-7 mm; phyllaries in 5-6 series, lanceolate to ovate, hard, glabrous, generally sticky, tip rounded to acute, receptacle flat to concave, honeycombed, chaff 0 Flowers: Staminate flowers 18-35; corollas 4.2-5 mm; pappus 3-4.5 mm; Pistillate flowers 19-31; corollas 2.5-3.5 mm Fruit: achenes, cylindric, 2-2.6 mm, glabrous; ribs 10; pappus 7-10.8 mm, of many bristles > involucre Misc: Gravelly and sandy washes, roadsides; < 850 m; Jun-Oct References: J.C. Hickman, ed. The Jepson Manual.L. Benson & R. Darrow. Trees and Shrubs of the Southwestern Deserts. Kearney & Peebles. Arizona Flora. ASU specimens.