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chaparral broom, coyote brush, dwarf chaparral false willow

Great Plains false willow, willow-baccharis

Habit Shrubs, 15–450 cm (prostrate and mat-forming to erect and rounded, much branched). Shrubs, 100–300 cm (much branched).
Stems

spreading to ascending, dark brown, shiny, striate-angular, glabrous, often ± scurfy, usually resinous and sticky.

ascending, striate-angled, glabrous, smooth or minutely roughened, resinous.

Leaves

present at flowering;

sessile or short-petiolate;

blades (1- or 3-nerved) oblanceolate to obovate, the smaller 5–40 × 2–15 mm (thick), bases cuneate, margins entire or coarsely dentate (teeth 3–9 distal to middles), faces glabrous, gland-dotted, resinous.

present at flowering (numerous and well developed); short-petiolate;

blades (at least broader distinctly 3-nerved) oblong to oblanceolate, 25–70 × 5–10(–20) mm, bases tapering attenuate, margins usually serrate distally (teeth 1–3, coarse irregular, ca. 5 mm apart), sometimes entire, apices acute or obtuse, faces finely gland-dotted.

Involucres

hemispheric to campanulate;

staminate 3.2–5 mm, pistillate 3–6 mm.

narrowly obconic to campanulate;

staminate 4–7 mm, pistillate 5–9 mm.

Pistillate florets

19–43;

corollas 2.5–3.5 mm.

25–30;

corollas 3–4 mm.

Staminate florets

20–34, 3–4 mm.

20–25;

corollas 3–5 mm.

Phyllaries

ovate to lanceolate, 1–3 mm, margins yellowish, scarious, medians yellow proximally, green distally, apices obtuse to acute or acuminate (erose, abaxial faces papillose-scurfy).

lanceolate, 2–6 mm, margins scarious, medians green or reddish, apices greenish or purplish, often erose-ciliate, faces glabrous, gland-dotted, resinous.

Heads

(100–200+) in (leafy) paniculiform arrays.

(100–200+, short-pedunculate or sessile) in (large, crowded, leafy) paniculiform arrays.

Cypselae

1–2 mm, 8–10-nerved, glabrous;

pappi 6–9 mm.

1.2–2 mm, irregularly 8–10-nerved, glabrous;

pappi 8–12 mm (elongating in fruit).

Baccharis pilularis

Baccharis salicina

Phenology Flowering May–Nov.
Habitat Stream banks, alkaline meadows, roadsides
Elevation 300–1600 m (1000–5200 ft)
Distribution
from FNA
CA; NM; OR; nw Mexico
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; CA; CO; KS; NM; NV; OK; TX; UT; Mexico (Baja California, Chihuahua, Coahuila, Durango, Sonora)
[WildflowerSearch map]
[BONAP county map]
Discussion

Subspecies 2 (2 in the flora).

Baccharis pilularis can be distinguished by its dark brown stems, and serrate, obovate to oblanceolate leaves. In addition, plants from some dunes of the California coast are prostrate, a growth form unique to this genus in our region.

The common, weedy, widespread form is subsp. consanguinea, which is typically erect, with its larger leaves 15–40 mm. Subspecies pilularis is known only from exposed sandy dunes and bluffs along the central coast of California. Its growth habit is matlike, and its larger leaves are 5–15 mm. The prostrate habit of subsp. pilularis is strikingly different from the upright habit of subsp. consanguinea.

C. B. Wolf (1935) demonstrated that in at least some populations, the distinction between prostrate and erect forms has a genetic basis. Transplants from the wild of the prostrate and erect forms retained their respective growth habits when grown together in a sheltered location and the morphology of seedlings reflected the habit of the parents. Wolf’s arguments for recognizing the forms as subspecies are further supported by the existence of prostrate cultivars in the horticultural trade. On the other hand, both erect and prostrate forms grow in proximity throughout the range of subsp. pilularis. In many areas the forms intergrade completely; in others they can be easily distinguished. Two subspecies are recognized here, notwithstanding difficulties in identifying habit from pressed specimens, or by observations of populations where both growth forms coexist. Further study is needed, perhaps utilizing molecular characters and detailed observations of native populations.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Baccharis salicina is recognized by its narrow, gland-dotted leaves with 1–3 irregular teeth on the distal half, heads in loose leafy arrays, campanulate involucres, and cypselae with 8–10 ribs.

The recognition of Baccharis emoryi as a separate species in other floras has been based on its wider, glabrous, eglandular leaves, more cylindric pistillate involucres, and dense whitish pappi. It was said to occur both west of the Rocky Mountains and in western Texas. In our study, expressions of the characters used to distinguish B. emoryi from other species were found to be inconsistent and inadequate to warrant recognition as a distinct species. There appears to be a complex of up to four species—emoryi, salicina, neglecta and angustifolia—that intergrade from west to east. Characteristics progress from broader leaves and larger heads (emoryi form of salicina) to narrow leaves with small heads (neglecta, angustifolia). The delimitation of taxa within this complex merits further investigation.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Key
1. Stems erect, rarely prostrate, brittle, forming erect or rounded shrubs; leaves mostly 15–40 mm; noncoastal and coastal California, Oregon
subsp. consanguinea
1. Stems prostrate, flexible, forming mats; leaves mostly 5–15 mm; sandy, exposed habitats of coastal California
subsp. pilularis
Source FNA vol. 20, p. 29. FNA vol. 20, p. 32.
Parent taxa Asteraceae > tribe Astereae > Baccharis Asteraceae > tribe Astereae > Baccharis
Sibling taxa
B. angustifolia, B. bigelovii, B. brachyphylla, B. dioica, B. glomeruliflora, B. glutinosa, B. halimifolia, B. havardii, B. malibuensis, B. neglecta, B. plummerae, B. pteronioides, B. salicifolia, B. salicina, B. sarothroides, B. sergiloides, B. texana, B. thesioides, B. vanessae, B. wrightii
B. angustifolia, B. bigelovii, B. brachyphylla, B. dioica, B. glomeruliflora, B. glutinosa, B. halimifolia, B. havardii, B. malibuensis, B. neglecta, B. pilularis, B. plummerae, B. pteronioides, B. salicifolia, B. sarothroides, B. sergiloides, B. texana, B. thesioides, B. vanessae, B. wrightii
Subordinate taxa
B. pilularis subsp. consanguinea, B. pilularis subsp. pilularis
Synonyms B. salicifolia, B. emoryi
Name authority de Candolle: in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 5: 407. (1836) Torrey & A. Gray: Fl. N. Amer. 2: 258. (1842)
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