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.

HIERACIUM

HAWKWEED

G. Ledyard Stebbins

Perennial; sap milky; herbage generally long-hairy
Stems erect, 1–10 dm
Leaves basal or cauline, alternate
Inflorescence: heads ligulate, few–many in cymes or panicles; involucre cylindric; phyllaries in 2–4 series of different lengths; receptacle naked
Flowers few–many; ligules yellow, white, or orange, readily withering
Fruit cylindric, slender; pappus of many slender bristles, brittle, dull white, tawny, or brownish
Species in genus: ± 250 species: ± worldwide
Etymology: (Greek: hawk)
Many reproduce only by asexual seeds.

Native

H. albiflorum Hook.

Stolons 0
Stems 4–8 dm; lower part densely hairy
Leaves mostly basal, 0.8–1.5 dm, oblong to oblanceolate, entire or few-toothed, coarsely long-hairy; cauline generally restricted to lower part of stem, smaller, upper part of stem nearly or quite leafless
Inflorescence: heads few–many, in open cymes or panicles; involucres 9–10 mm; phyllaries glabrous or glandular
Flowers generally 15–30; ligules white
Fruit 2–3 mm, red-brown; pappus dull white or tawny
Chromosomes: 2n=18
Ecology: Dry forests
Elevation: 0–2900 m.
Bioregional distribution: California Floristic Province, Warner Mountains
Distribution outside California: to Alaska, Colorado
Horticultural information: DRN, SHD: 1, 2, 3, 7, 8, 9, 10, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24.