Baccharis pilularis

de Candolle in A. P. de Candolle and A. L. P. P. de Candolle

in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 5: 407. 1836.

Common names: Chaparral broom coyote brush dwarf chaparral false willow
Treatment appears in FNA Volume 20. Treatment on page 29. Mentioned on page 24, 25.

Shrubs, 15–450 cm (prostrate and mat-forming to erect and rounded, much branched). Stems spreading to ascending, dark-brown, shiny, striate-angular, glabrous, often ± scurfy, usually resinous and sticky. Leaves present at flowering; sessile or short-petiolate; blades (1-nerved 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. Heads (100–200+) in (leafy) paniculiform arrays. Involucres hemispheric to campanulate; staminate 3.2–5 mm, pistillate 3–6 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). Staminate florets 20–34, 3–4 mm. Pistillate florets 19–43; corollas 2.5–3.5 mm. Cypselae 1–2 mm, 8–10-nerved, glabrous; pappi 6–9 mm.

Distribution

V20-19-distribution-map.gif

Calif., N.Mex., Oreg., nw Mexico

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.

Key

1 Stems erect, rarely prostrate, brittle, forming erect or rounded shrubs; leaves mostly 15–40 mm; noncoastal and coastal California, Oregon Baccharis pilularis subsp. consanguinea
1 Stems prostrate, flexible, forming mats; leaves mostly 5–15 mm; sandy, exposed habitats of coastal California Baccharis pilularis subsp. pilularis
... more about "Baccharis pilularis"
not tailed +, rounded +  and obtuse +
distinct +
subequal +
scarious +
usually triangular +  and linear +
usually deltate +  and lanceolate +
paniculiform +
indeterminate +  and determinate +
Scott D. Sundberg† +  and David J. Bogler +
de Candolle in A. P. de Candolle and A. L. P. P. de Candolle +
cuneate +
3-nerved +  and 1-nerved +
0.5 cm5 mm <br />0.005 m <br /> (4 cm40 mm <br />0.04 m <br />) +
oblanceolate;obovate +
smaller +
2mm;15mm +
rugulose +  and muricate +
barbellulate +  and barbellate +
Chaparral broom +, coyote brush +  and dwarf chaparral false willow +
not 2-lipped +  and actinomorphic +
whitish +, white +  and pale-yellow +
0.25 cm2.5 mm <br />0.0025 m <br /> (0.35 cm3.5 mm <br />0.0035 m <br />) +
beaked +, 2-ribbed +  and 5-ribbed +
compressed +, obovoid +  and cylindric +
fertile +  and bisexual +
Calif. +, N.Mex. +, Oreg. +  and nw Mexico +
resinous +
gland-dotted +
pistillate +  and staminate +
winged +  and beaked +
dispersed +
racemiform +, corymbiform +  and paniculiform +
indeterminate +
heterogamous +  and homogamous +
each +  and sessile +
pistillate +  and staminate +
0.3 cm3 mm <br />0.003 m <br /> (0.9 cm9 mm <br />0.009 m <br />) +
hemispheric;campanulate +
0.3 cm3 mm <br />0.003 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
short-petiolate +  and sessile +
spreading-reflexed;spreading-reflexed +
less deltate +  and lanceovate +
dentate +  and entire +
hispid +  and glabrous +
green +  and yellow +
2-carpellate +
brownish +, whitish +  and tawny +
persistent +
25 +  and 50 +
0.6 cm6 mm <br />0.006 m <br /> (0.9 cm9 mm <br />0.009 m <br />) +
ovate +  and lanceolate +
0.1 cm1 mm <br />0.001 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. +
styliferous +, neuter +  and pistillate +
bearing subulate enations +, hairy +  and bristly +
conic;tholiform;conic;tholiform;flat +
wolf1935a +
exalbuminous +
1 (?) +  and 20 (?) +
resinous +
dark-brown +
spreading +  and ascending +
appendaged +  and truncate +
papillate +  and smooth +
Compositae +
Baccharis pilularis +
Baccharis +
species +