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.

ARNICA

Theodore M. Barkley

Perennial generally from long, naked rhizome
Leaves: basal 0 or generally withered by flower; cauline opposite
Inflorescence ± flat-topped; heads radiate or discoid, 1–many; involucre hemispheric to obconic; phyllaries generally in 2 ± equal series; receptacle ± flat, naked
Ray flowers (0)6–21; ligules (orange-)yellow
Disk flowers many; corolla generally soft-hairy, colored like ligules; anther bases entire or slightly sagittate, tips triangular; style branches flat, tips truncate, very short, hair-tufted
Fruit ± cylindric, 5–10-veined; pappus of many barbed to subplumose bristles, white to red-brown
Species in genus: ± 27 species: North America, Eurasia
Etymology: (Latin or Greek: ancient name)
Reference: [Downie & Denford 1988 Rhodora 90:245–275]
Diploid species sexual; polyploid species generally form seeds asexually.

Native

A. amplexicaulis Nutt.

Plant 3–8 dm from short rhizome or caudex, generally hairy and glandular, especially upward
Stems 1–few, sometimes branched above middle
Leaves: basal petioled; cauline 5–10 pairs, ± sessile, 4–12 cm, ± elliptic to ovate, ± toothed
Inflorescence: heads radiate, (3)4–9+; involucre 9–15 mm, bell-shaped or widely obconic; phyllaries acute, tip hairier
Ray flowers 8–14; ligules 1–2 cm
Fruit 4–6 mm, sparsely hairy, sometimes glandular; pappus subplumose, brownish
Chromosomes: 2n=38,57,76
Ecology: Moist, open woodlands, streambanks
Elevation: 2200–3500 m.
Bioregional distribution: Klamath Ranges, High Cascade Range, High Sierra Nevada, East of Sierra Nevada
Distribution outside California: to s Alaska, Montana
Flowering time: Jul–Aug
Generally asexual
Horticultural information: TRY.