Jepson Flora Project: Jepson Interchange    

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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.



Elizabeth McClintock

Annual, perennial herb, sometimes woody at base, often aromatic, glabrous or hairy
Stems decumbent or erect, branched
Leaves alternate, dissected
Inflorescence: heads disciform, radiate, or discoid, few–many; phyllaries in 2–3 overlapping series; receptacle convex to conic, generally dotted with tubercles
Pistillate or ray flowers many; corollas tubular or with inconspicuous to well developed ligules, yellow or white
Disk flowers many; corollas tubular, yellow; anther tips ovate, bases rounded or ± cordate; style branches truncate with shrub-like tips
Fruit generally 3–10-ribbed; pappus a crown of short scales
Species in genus: 70 species: Eur, Asia, North America
Etymology: (Latin: immortality)
See also Sphaeromeria.


T. parthenium (L.) Sch.Bip.


Perennial, strongly aromatic, ± glabrous to finely hairy; caudex woody
Stems < 1 m, ridged, branched
Leaves 4–10 cm, 1.5–4 cm wide, ovate in outline, petioled, 2-pinnate; uppermost generally 1-pinnate, 1° leaflets ovate, generally 3–5, coarsely rounded or acute
Inflorescence: heads radiate, 10–30 in rounded or flat-topped clusters, < 2 cm diam; phyllaries in 2–3 series, leathery, sparingly hairy, margins transparent
Ray flowers: ligules < 8 mm, white
Disk flowers: corolla 2 mm, yellow
Fruit 2 mm, cylindric, 5–10-ribbed; pappus a crown, < 0.5 mm or 0
Chromosomes: 2n=18
Ecology: Common. Disturbed urban areas, roadsides, fields
Elevation: generally < 250 m.
Bioregional distribution: Klamath Ranges, North Coast Ranges, n Sierra Nevada Foothills, Great Central Valley, San Francisco Bay Area, Outer South Coast Ranges, South Coast
Distribution outside California: native to Europe
Long cultivated in Eur and US as ornamental and for medicine
Synonyms: Chrysanthemum p. (L.) Bernardi

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