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.



Perennial, subshrubs
Stems 1–many, erect, ± hairy
Leaves simple, alternate, entire or pinnately lobed, ± soft-hairy; upper often ± glandular
Inflorescence: heads radiate, solitary or in cymes; peduncles short to long; involucre cylindric to bell-shaped; phyllaries 5–13 in 1–2 subequal series; receptacle flat, naked
Ray flowers 2–6; corollas yellow, fading to cream, persistent on fruit; ligules ovate, 3-lobed, reflexed when dry
Disk flowers few–many; corollas yellow, densely hairy; anther tips triangular; style tips truncate
Fruit cylindric (or ray achenes slightly flat), ribbed, glabrous, glandular or soft-hairy; pappus of 4–6 unequal transparent scales
Species in genus: 6 species: sw US, n Mex
Etymology: (Greek: naked turn)
Reference: [Brown 1973 PhD dissertation AZ State Univ]


P. cooperi (A. Gray) Greene

Perennial, subshrub 2–6 dm
Stems densely white-tomentose, openly branched
Leaves 1–8 cm, linear, entire, tomentose or becoming glabrous
Inflorescence: heads 1–few; peduncles 3–8 cm; involucre 3–5 mm diam, cylindric; phyllaries in 2 series, outer 5–8, 6–8 mm, lanceolate, ± soft hairy, inner 4–5, shorter, membranous
Ray flowers 3–6; ligules 8–18 mm
Disk flowers 10–25; corollas 4–5 mm
Fruit 2–3 mm, glabrous or sparsely glandular; pappus scales 1–2 mm
Chromosomes: 2n=32
Ecology: Dry plains, hillsides, washes
Elevation: 150–1500 m.
Bioregional distribution: eastern Mojave Desert, Sonoran Desert
Distribution outside California: to Utah, Arizona, n Mexico
Flowering time: Apr–Jun, Oct–Dec
Horticultural information: DRN: 10, 11, 12, 13, 19, 20, 21 &DRY, SUN: 7, 8, 9, 14, 18.

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