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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.


G. Ledyard Stebbins

Species in genus: 1 sp.: w North America
Etymology: (Latin: diminutive of Prenanthes )


P. exigua (A. Gray) Rydb.

Annual, 1–4 dm; sap milky
Stems slender, generally openly much-branched, sparsely glandular-puberulent
Leaves: basal, 2–4 cm, oblanceolate, entire to pinnately lobed, ciliate, otherwise glabrous, often early-deciduous; cauline few, reduced, upper scale-like
Inflorescence: heads ligulate, many, in open panicles; peduncles very slender; involucre cylindric, 4–5 mm; phyllaries in 2 series, outer 2–3, < 1 mm, inner 3–4, 4–5 mm, lanceolate; receptacle naked
Flowers 3–4; ligules light pink or white, readily withering
Fruit 3–4 mm, cylindric, 5-ribbed, white; pappus of fine bristles, 2–4 mm, white
Chromosomes: 2n=14
Ecology: Desert canyons and valleys, juniper woodlands
Elevation: < 1850 m.
Bioregional distribution: East of Sierra Nevada, Desert
Distribution outside California: to Utah, Colorado, w Texas
Flowering time: Mar–May
Synonyms: Lygodesmia e. A. Gray
Reference: [Tomb 1972 Brittonia 24:223–228]

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