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

  • Up-to-date information about California vascular plants is available from the Jepson eFlora.



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.



Annual, perennial herb, shrubs
Stems slender to stout and fleshy
Leaves simple to several times pinnately dissected, basal or cauline, opposite or less commonly alternate, sessile or petioled
Inflorescence: heads radiate, solitary or in few–many-headed cymes; peduncles short to long; involucre hemispheric or bell-shaped; phyllaries in 2 series, outer ± spreading, thick, green, inner thin, membranous; receptacle flat to rounded, chaffy; scales flat, scarious
Ray flowers fertile or sterile; ligules generally yellow, showy
Disk flowers many; corollas 4–5-lobed, yellow; style tips truncate to long-tapered
Fruit: ray and disk achenes alike or different, generally compressed front-to-back, often winged; pappus 0 or of 2 awns or scales
Species in genus: ± 114 species: Am, Africa
Etymology: (Greek: bedbug-like, from fruit)
Reference: [Smith 1984 Sida 10:276–289]


C. hamiltonii (Elmer) H. Sharsm.


Annual 5–25 cm, glabrous
Stems 1–many, erect
Leaves basal (or few cauline, alternate); petiole 1–3 cm; blade 5–20 mm, 1–2-pinnately divided into linear segments 1 mm wide, grooved above
Inflorescence: heads solitary, ± scapose; involucre cylindric, base truncate; outer phyllaries 4–7, 3–6 mm, linear; inner phyllaries 6–8, 5–8 mm, ovate, acute, margin scarious; chaff scales generally 5–6 mm, linear, free from disk achenes
Ray flowers 5–8, fertile; ligules 3–8 mm, oblong to obovate, reflexed, yellow
Disk flowers 20–30; corollas ± 3–4.5 mm, yellow
Fruit: ray achenes 5 mm, obovate, brown or tan splotched with brown, smooth, glabrous, shiny; wing narrow; pappus 0; disk achenes 5–6 mm, obovate, tan splotched with brown, shiny, both surfaces covered with ascending hairs, margins ciliate, hairs 1–1.5 mm; pappus scales ± 1 mm, obovate
Chromosomes: 2n=24
Ecology: Dry exposed slopes
Elevation: 600–1300 m.
Bioregional distribution: e San Francisco Bay Area (Diablo Range)
Horticultural information: In cultivation.
See the CNPS Inventory for information about endangerment and rarity.
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bioregional map for COREOPSIS%20hamiltonii being generated

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