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.

PENTACHAETA

Meredith A. Lane

Annual from slender taproot, ± hairy (but appearing glabrous)
Stems generally simple or branching in lower half of plant, erect, generally flexible, glabrous to hairy, green to reddish
Leaves generally narrowly linear, ciliate, green
Inflorescence: heads radiate, disciform or discoid, nodding in bud, solitary, terminal; peduncles slender; involucres 3–7 mm, generally bell-shaped; phyllaries in 2–3 generally equal series, lanceolate to (ob)ovate, green, margins widely scarious; receptacle naked
Ray flowers present or 0, or corolla reduced to tube; corollas white, yellow, or reddish
Disk flowers few–many; corollas yellow to reddish or maroon; style tips linear, acute
Fruit 1.5–3 mm, oblong-fusiform, generally compressed, generally hairy; pappus of 0–20 fragile, slender bristles
Species in genus: 6 species: CA
Etymology: (Greek: five bristles, from pappus)
Reference: [Van Horn 1973 Univ Calif Publ Bot 65:1–41]

Native

P. aurea Nutt.

GOLDEN-RAYED PENTACHAETA

Stems 5–36 cm, short-hairy
Leaves < 5.5 cm, 3 mm wide; upper surface glabrous to sparsely long-hairy; lower surface glabrous to very hairy
Inflorescence: heads < or = 22 per plant; peduncles short-hairy; involucres widely obconic; phyllaries ovate-elliptic, glabrous or sparsely short-hairy
Ray flowers 14–52; ligules 3–12 mm, yellow to brownish orange, rarely white
Disk flowers 30–90; corollas 5-lobed, yellow
Fruit: pappus bristles 5–8, expanded at base
Chromosomes: 2n=18
Ecology: Grassy areas
Elevation: < 1850 m.
Bioregional distribution: San Gabriel Mountains, San Bernardino Mountains, Peninsular Ranges
Synonyms: Chaetopappa a. (Nutt.) D.D. Keck
Horticultural information: TRY.