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.
FNA 2006, Benson and Darrow 1981, Kearney and Peebles 1969
Common Name: desertbroom Duration: Perennial Nativity: Native Lifeform: Shrub Wetland Status: FACU General: Dioecious, broomlike shrubs 2-2.5 m tall; stems numerous, green and resinous distally, often nearly leafless; twigs longitudinally striate-ridged. Leaves: Alternate, sessile, few, and quickly deciduous; blades linear to linear-lanceolate, up to 2 cm long; larger leaves often minutely toothed, but most leaves are much smaller or reduced to scales. Flowers: Flower heads unisexual, discoid, and solitary on branch tips or arranged in dense panicles; involucre (the ring of bracts surrounding the flower head) cylindric (pistillate) to hemispheric (staminate), 3-8 mm long, the bracts (phyllaries) ovate to lanceolate, 1-5 mm long, yellowish-green in the middle, with yellowish, slightly scarious margins and rounded tips. Pistillate florets white, and staminate flowers yellowish. Fruits: Achenes 10-ribbed, 2 mm long, with a pappus of bristles, 1 cm long, attached to the top. Ecology: Found in sandy-gravelly washes, watercourses, shallow drainages, flats, low hills, and roadsides, sometimes in saline soil from 1,000-5,500 ft (305-1676 m); flowers September-December. Distribution: s CA, s NV, AZ, s NM, sw TX; south to c MEX. Notes: Baccharis is a genus of shrubs with male and female flowers on separate plants, gland-dotted leaves, all disc flowers, and a pappus of bristles on the seeds. Desert broom is a conspicuous shrub of many southwest deserts, often growing along highways and dry washes. Distinguished by its broom-like growth form with many erect-ascending branches; and leaves mostly small and spatulate or absent from stems, as they tend to fall off before the plant flowers in late summer. Because of its evergreen nature, the species is often used as an ornamental; it is not particularly palatable to livestock. Ethnobotany: Infusions were used for coughs and stomach aches; stems were used to make arrows or tied together in bundles to make brooms. Etymology: Baccharis is named for Bacchus, the god of wine, sarothroides means broom-like. Synonyms: None Editor: SBuckley 2010, FSCoburn 2015, AHazelton 2015