Baccharis sarothroides |
Baccharis havardii |
|
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broom baccharis, desert broom, greasewood, groundsel, rosin-brush |
Havard's false willow |
|
Habit | Shrubs, 100–400 cm (much branched, broomlike). | Subshrubs, 15–70 cm (much branched from bases). |
Stems | erect, striate, sharply angled, green distally, glabrous, resinous. |
erect (green to tan), slender, striate-angled, 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. |
present at flowering; short-petiolate; blades (1-nerved) narrowly spatulate to linear, 20–40 × 2–3 mm, reduced to bracts distally, bases attenuate, margins entire or toothed (teeth to 2 mm), faces glabrous, gland-dotted, resinous. |
Involucres | cylindric to hemispheric; staminate 4–5.2 mm, pistillate 3–8 mm. |
cylindro-campanulate; staminate 3 mm, pistillate 4–4.5 mm. |
Pistillate florets | 19–31; corollas 2.5–3.5 mm. |
15–20; corollas 3 mm. |
Staminate florets | 18–35; corollas 4.2–5 mm. |
12–15; corollas 3–4 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). |
lanceolate, 1–4 mm, margins scarious, medians green or brownish, apices obtuse to acuminate (thickened, slightly erose and ciliate). |
Heads | borne singly (on nearly leafless branches) or (laterally on branchlets) in dense paniculiform arrays. |
in broad paniculiform arrays. |
Cypselae | 2–2.6 mm, finely 8–10-nerved, glabrous; pappi 7–12 mm. |
2–2.5 mm, 5-nerved, glabrous; pappi 4 mm. |
2n | = 18. |
|
Baccharis sarothroides |
Baccharis havardii |
|
Phenology | Flowering Aug–Nov. | Flowering Jul–Sep. |
Habitat | Gravelly and sandy washes, roadsides, railroads, mesquite flats, chaparral | Dry rocky hillsides, open ground, calcareous gravels |
Elevation | 50–1500 m (200–4900 ft) | 1500–2300 m (4900–7500 ft) |
Distribution |
AZ; CA; NM; TX; Mexico (Baja California, Baja California Sur, Sinaloa, Sonora)
|
NM; TX; Mexico (Chihuahua) |
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. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Found mainly in the Chisos and Davis Mountains of West Texas, Baccharis havardii is distinguished by its short bushy habit, narrow leaves with elongate teeth, and 5-nerved cypselae. G. L. Nesom (pers. comm.) suggested that it is weakly defined and further investigation may demonstrate it should be included in the Mexican species B. sulcata de Candolle (which name would have priority over B. havardii). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 20, p. 33. | FNA vol. 20, p. 28. |
Parent taxa | ||
Sibling taxa | ||
Name authority | A. Gray: Proc. Amer. Acad. Arts 17: 211. (1882) | A. Gray: in A. Gray et al., Syn. Fl. N. Amer. 1(2): 224. (1884) |
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