Baccharis sarothroides

A. Gray

Proc. Amer. Acad. Arts 17: 211. 1882

Common names: Greasewood rosin-brush groundsel desertbroom
Treatment appears in FNA Volume 20. Treatment on page 33. Mentioned on page 25.
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.

Phenology: Flowering Aug–Nov.
Habitat: Gravelly and sandy washes, roadsides, railroads, mesquite flats, chaparral
Elevation: 50–1500 m

Distribution

V20-28-distribution-map.gif

Ariz., Calif., N.Mex., Tex., Mexico (Baja California, Baja California Sur, Sinaloa, Sonora).

Discussion

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.

References

None.

Lower Taxa

No lower taxa listed.