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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.

HEMIZONIA

TARPLANT, TARWEED

Annual to shrub, generally glandular, aromatic
Stems generally branched above middle or throughout
Leaves generally cauline (some also basal and cauline), generally alternate, generally linear to (ob)lanceolate, entire to pinnately lobed, generally not spine-tipped; lower generally toothed to lobed; upper generally entire
Inflorescence: heads radiate, generally 1–many in open cymes; involucre generally hemispheric; phyllaries generally linear to lanceolate, half-enclosing ray fruits; chaff scales generally in 1 ring between ray and disk flowers (scattered)
Ray flowers 3–many; ligules generally 3-lobed, white to yellow
Disk flowers 3–many, staminate or fruiting; corollas white to yellow, becoming red; anther tips ovate; style branches long, tips bristly
Fruit: ray achenes ± 3-angled; pappus 0; disk achenes cylindric or obconic, pappus 0 or scales generally linear to lanceolate
Species in genus: ± 25 species: CA, OR, w AZ, n Baja CA
Etymology: (Greek: half girdle, from sheathing phyllaries)
Reference: [Tanowitz 1982 Syst Bot 7:314–339; Venkatesh 1958 Amer J Bot 45:77–84]
Recent taxonomic note: *See revised taxonomy of Baldwin 1999 Novon 9:462–471.

Native

H. pungens (Hook. & Arn.) Torr. & A. Gray

COMMON SPIKEWEED

Annual 1–12 dm
Stems: branches generally stiff, bristly
Leaves: lower 5–15 cm, linear-lanceolate, deeply 2 X divided; upper linear, spine-tipped, glabrous to scabrous, margin stiff-ciliate, generally with axillary leaf clusters
Inflorescence sometimes dense; heads ± clustered; involucre 3–6 mm, generally overtopped by upper leaves; phyllaries keeled, spine-tipped, scabrous; chaff scales scattered, generally spine-tipped
Ray flowers many; ligule 3–5 mm, 2-lobed, yellow
Disk flowers many, generally staminate; corollas and anthers yellow
Fruit ± 2 mm, beaked; disk pappus 0
Chromosomes: 2n=18
Ecology: Grassland, depressions, marshes
Elevation: < 500 m.
Bioregional distribution: s North Coast Ranges, Cascade Range Foothills, Great Central Valley, n Central Coast, San Francisco Bay Area, South Coast Ranges, alien in Southwestern California
Distribution outside California: to Washington
Recent taxonomic note: *Centromadia pungens (Hook. & Arn.) Greene

Native

subsp. laevis D.D. Keck

SMOOTH TARPLANT


Leaves and bracts not scabrous
Inflorescence: heads generally 4–6 mm diam, solitary or few in loose clusters along inflorescence branches; chaff scales not spine-tipped
Chromosomes: 2n=18
Ecology: Grassland
Elevation: < 400 m.
Bioregional distribution: South Coast, Peninsular Ranges
Synonyms: H. l. (D.D. Keck) D.D. Keck
Threatened by flood-control, development
Recent taxonomic note: *Centromadia pungens (Hook. & Arn.) Greene subsp. laevis (D.D. Keck) B.G. Baldwin

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