TREATMENT FROM THE JEPSON MANUAL (1993) previous taxon | next taxon
Jepson Interchange (more information)
©Copyright 1993 by the Regents of the University of California
For up-to-date information about California vascular plants, visit the Jepson eFlora.

    THIS PAGE IS NO LONGER UPDATED
    AND IS MAINTAINED FOR ARCHIVAL PURPOSES ONLY
  • 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.

CENTAUREA

KNAPWEED, STAR-THISTLE

David J. Keil and Charles E. Turner

Annual to perennial herb, ± branched
Leaves alternate; lower generally deeply 1–2-lobed, segments generally narrow; upper reduced
Inflorescence: heads discoid (sterile outer flowers sometimes ± ray-like); involucre cylindric to hemispheric; phyllaries many, graded, generally ± ovate, scarious-margined, tip appendages fringed to spiny; receptacle flat, long-bristly
Flowers: inner fruiting; anther bases tailed, tips oblong; style top minutely hairy, tips minutely branched
Fruit ± barrel-shaped, ± compressed, attached ± at side; pappus generally of stiff, unequal bristles or narrow scales
Species in genus: ± 500 species: especially Eurasia, n Africa (± 2 North America); some cultivated (waifs may including C. cineraria L., C. eriophora L., C. jacea L., C. moschata L., C. muricata L., C. salmantica L.)
Etymology: (Greek: ancient name)
Weedy.

Introduced

C. squarrosa Willd.

Perennial 2–5 dm, much-branched, scabrous, ± loosely tomentose
Leaves: lower 10–15 cm, deeply 1–2-lobed, generally 0 at flower
Inflorescence panicle-like; heads ± many; involucre 7–8 mm, ± cylindric; main phyllaries pale green to straw-colored (or tinged purple), appendages fringed with slender, straw-colored spines, tip-spine 1–3 mm
Flowers few; corollas 7–9 mm, equal (or sterile corollas ± larger), pink or pale purple
Fruit 2.5–3.5 mm, ± light brown; pappus bristles (0)2–2.5 mm, white
Chromosomes: 2n=18
Ecology: Disturbed places
Elevation: < 1400 m.
Bioregional distribution: Klamath Ranges, Cascade Range, Modoc Plateau
Distribution outside California: native to Asia
Weedy
Synonyms: C. virgata Lam. var. s. (Willd.) Boiss

previous taxon | next taxon
bioregional map for CENTAUREA%20squarrosa being generated
 


Retrieve Jepson Interchange Index to Plant Names entry for Centaurea squarrosa
Retrieve dichotomous key for Centaurea
Return to treatment index page
Glossary
University & Jepson Herbaria Home Page | Copyright © by the Regents of the University of California