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.

HYMENOTHRIX

Annual, biennial, perennial herb, taprooted
Stems 1–several from base, erect, simple or much-branched above
Leaves basal and cauline, alternate; lower petioled, pinnately or ternately dissected into narrow lobes; upper reduced, sessile
Inflorescence: heads radiate or discoid, in many-headed, ± flat-topped clusters; peduncles slender; involucre obconic to hemispheric; phyllaries in 1–2 ± equal series, free; receptacle rounded, naked
Ray flowers 0 (in CA) or few; ligules yellow
Disk flowers few–many; corollas white to yellow; anther tips triangular; style tips narrowly triangular
Fruit club-shaped, 4–5-angled, ± hairy; pappus of 10–15 bristle-tipped scales
Species in genus: 5 species: sw US, Mex
Etymology: (Greek: membranous bristle, from pappus)
Reference: [Turner 1962 Brittonia 14:101–119]

Native

H. wrightii A. Gray

Biennial, perennial herb < or = 1.5 m, glabrous to densely glandular or soft-hairy
Leaves densely crowded on lower stem; lobes generally 1 mm wide or less; margins rolled under
Inflorescence: peduncle 1–7 cm; bracts scattered, scale-like; involucre hemispheric; phyllaries 3–8 mm, oblanceolate to obovate, obtuse, tips generally purple, glabrous or glandular
Flowers: corollas 5–8 mm, outer and inner equal, white or purple-tinged, lobes linear, spreading; anthers ± 3 mm, dark purple
Fruit 3–6 mm; pappus scales 3–7 mm
Chromosomes: 2n=24
Ecology: Open slopes
Elevation: ± 1500 m.
Bioregional distribution: s Peninsular Ranges (Cuyamaca, Laguna mtns)
Distribution outside California: to New Mexico, n Mexico
Horticultural information: TRY.