Jepson Flora Project: Jepson Interchange    

 
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©Copyright 1993 by the Regents of the University of California

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  • Up-to-date information about California vascular plants is available from the Jepson eFlora.

ASTERACEAE

SUNFLOWER FAMILY

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.

ONOPORDUM

David J. Keil and Charles E. Turner

Biennial, coarse
Stem spiny-winged
Leaves basal and cauline, alternate, dentate to deeply pinnately lobed, very spiny
Inflorescence: heads discoid, 1–7, in cymes, in CA; involucre 3–7 cm diam, (hemi)spheric; phyllaries many, in several series, spine-tipped, outer generally spreading or reflexed; receptacle naked, deeply pitted
Flowers many; corollas (nearly) radial, white to purple, tube slender, lobes linear; anther base acutely tailed, tips awl-shaped; style tip with minutely hairy node, terminal appendage subentire, long, cylindric, minutely papillate
Fruit ± cylindric, 4–5-angled, glabrous, generally ± cross-roughened, brown to gray-black, mottled; pappus bristles many, barbed or plumose, fused at base
Species in genus: ± 40 species: Eurasia, Medit
Etymology: (Greek: name for cotton thistle)
Weedy.

Introduced

O. illyricum L.

ILLYRIAN THISTLE

Plant < 25 dm, canescent-tomentose
Leaves 1–5 dm, (deeply) pinnately lobed (lobes 8–10 pairs, triangular, entire or again lobed)
Inflorescence: phyllaries lanceolate to ovate, glabrous or ± cobwebby, spines < 5 mm
Flowers: corollas 25–35 mm, purple, lobes glandular-puberulent
Fruit 4–5 mm; pappus 10–12 mm, ± white
Chromosomes: 2n=34
Ecology: Disturbed sites
Elevation: < 500 m.
Bioregional distribution: s San Francisco Bay Area
Distribution outside California: native to se Europe

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bioregional map for ONOPORDUM%20illyricum being generated
 


Retrieve Jepson Interchange Index to Plant Names entry for Onopordum illyricum
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