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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.


Guy L. Nesom

Species in genus: 1 sp.: sw US, Mex, C.Am
Etymology: (Latin: green thorns)
Reference: [Nesom et al. 1991 Phytologia 70:371–381]


C. spinosa (Benth.) G.L. Nesom var. spinosa

Subshrub from stout rhizome, ± glabrous
Stems erect, 5–15(25) dm; branches sometimes thorn-like
Leaves alternate, 10–50 cm, oblanceolate, generally entire, 1-veined, early deciduous
Inflorescence: heads radiate, few–many in loose clusters; phyllaries in (3)4–5 series, inner 4.5–7.5 mm, ± lanceolate, veins (1)3(5), parallel, orange-resinous, tips generally rounded, margins transparent; receptacle naked
Ray flowers 10–33; corollas 4–8(11) mm, white, ligules 1–2 mm wide, coiled at maturity
Disk flowers many; corollas 3–6 mm, yellow; style appendages ± deltate
Fruit 1.5–3.5 mm, slightly compressed, glabrous; veins 5(6), whitish to golden-brown; pappus of many barbed bristles in ± 2 series, outer generally << inner
Chromosomes: 2n=18
Ecology: Seeps, moist streamsides, ditches, sometimes saline or drier areas
Elevation: < 1250 m.
Bioregional distribution: Peninsular Ranges, Sonoran Desert
Distribution outside California: to Utah, south-central US, Mexico
Flowering time: Jun–Dec
Synonyms: Aster s. Benth

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