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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.


A. Michael Powell

Perennial, shrubs
Leaves generally opposite; blade elliptic to triangular, margin entire to lobed
Inflorescence: heads discoid, solitary or in ± flat-topped cymes; phyllaries subequal, in 1–2(3) series; receptacle flat to conic, naked
Flowers 10–60; corollas ± white or blue to pink-tinged, cylindric (or throat wider)
Fruit 5-angled, generally 5-ribbed; pappus of 5–40 slender scabrous bristles, often easily detached
Etymology: (Latin: resembling Ageratum )
Reference: [King & Robinson 1987 Monogr Syst Bot Missouri Bot Garden 22:428–436]


A. adenophora (Spreng.) R.M. King & H. Rob.

Perennial; base woody
Stem generally 5–15 dm, erect, ± purple, glandular-hairy
Leaves opposite; blade deltoid-ovate, serrate, purple below, glandular-puberulent, especially below
Inflorescence: heads ± 6.5 mm, clustered; phyllaries glandular-puberulent
Flower: corollas white, pink-tinged
Fruit 1.7–2 mm
Chromosomes: 3n=51(n=17)
Ecology: Disturbed places
Elevation: generally < 300 m.
Bioregional distribution: Central Coast, San Francisco Bay Area, Outer South Coast Ranges, South Coast
Distribution outside California: native of Mexico, widely naturalized
Synonyms: Eupatorium a. Spreng
Reproduces by asexual seed; cultivated as ornamental; may be seriously invasive in mild coastal situations.

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