11.
Baccharis pilularis
de Candolle in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 5: 407. 1836.
Chaparral broom, coyote brush, dwarf chaparral false willow
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- 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.
Subspecies 2 (2 in the flora): w United States, nw Mexico.
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
.
SELECTED REFERENCE
Wolf, C. B. 1935. Observations on
Baccharis pilularis
DC. Occas. Pap. Rancho Santa Ana Bot. Gard. 1: 17—29.
