Jepson Flora Project: Jepson Interchange    

 
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Jepson Interchange (more information)
©Copyright 1993 by the Regents of the University of California
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ASTERACEAE

SUNFLOWER FAMILY

David J. Keil, Family Editor and author, except as specified

Annual to tree
Leaves basal or cauline, alternate to whorled, simple to compound
Inflorescence: 1° inflorescence a head, each resembling a flower, 1–many, generally arrayed in cymes, generally subtended by ± calyx-like involucre; flowers 1–many per head
Flowers bisexual, unisexual, or sterile, ± small, of several types; calyx 0 or modified into pappus of bristles, scales, or awns, which is generally persistent in fruit; corolla radial or bilateral (rarely 0), lobes generally (0)4–5; stamens 4–5, anthers generally fused into cylinder around style, often appendaged at tips, bases, or both, filaments generally free, generally attached to corolla near throat; pistil 1, ovary inferior, 1-chambered, 1-seeded, style 1, branches 2, generally hair-tufted at tip, stigmas 2, generally on inside of style branches
Fruit: achene, cylindric to ovoid, generally deciduous with pappus attached
Genera in family: ± 1300 genera, 21,000 species (largest family of dicots): worldwide. Largest family in CA. Also see tribal key to CA genera: Strother 1997 Madroño 44(1):1–28. See glossary p. 25 for illustrations of general family characteristics.

BIDENS

STICKTIGHT, SPANISH-NEEDLES, BEGGAR'S TICK

Annual, perennial herb, shrubs
Stems prostrate to erect
Leaves simple or pinnate, generally opposite, sessile or petioled
Inflorescence: heads radiate or discoid, generally few in CA; involucre cylindric to bell-shaped; phyllaries in 2 dissimilar series, outer generally ± leaf-like in texture, inner thinner, with transparent or scarious margins; receptacle chaffy; chaff scales narrow, flat
Ray flowers 0 or few; ligules yellow or white
Disk flowers generally many; corollas yellow, radial (or outermost white, bilateral)
Fruit narrowly club-shaped, thick or compressed front-to-back; pappus 0 or awns 1–several, generally barbed
Species in genus: ± 230 species: worldwide
Etymology: (Latin: 2 teeth)
Reference: [Sherff & Alexander 1955 North America Flora 2(2):70–129]

Introduced

B. pilosa L. var. pilosa

COMMON BEGGAR-TICKS, SPANISH-NEEDLES

Annual, glabrous or ± soft-hairy
Stems erect, 3–18 dm, square
Leaves compound, petioled; axis sometimes winged; leaflets generally 3–5, 2–6 cm, lanceolate to ovate, acute, serrate, base often asymmetric
Inflorescence: heads discoid or radiate, few–many, erect; peduncles 1–9 cm; involucre 7–8 mm diam in flower, hemispheric; outer phyllaries 7–9, 4–5 mm, linear; inner phyllaries 4–7 mm, lanceolate; chaff scales linear, acuminate
Ray flowers 0 or vestigial; corolla white
Disk flowers alike; corolla ± 2 mm, radial, yellow (or not alike, with outer corollas 2–3 mm, white, ± bilateral)
Fruit 4–16 mm, narrowly club-shaped or slightly flat, 4-angled, black, short-rough-hairy; pappus awns 2–4, 2–4 mm, ± yellow
Chromosomes: 2n=72
Ecology: Disturbed sites
Elevation: generally < 750 m.
Bioregional distribution: South Coast Ranges, Southwestern California
Distribution outside California: subtropical, tropical worldwide

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bioregional map for BIDENS%20pilosa%20var.%20pilosa being generated
 
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Retrieve Jepson Interchange Index to Plant Names entry for Bidens pilosa var. pilosa
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Overlay Consortium of California Herbaria specimen data by county on this map
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