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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.



Meredith A. Lane

Subshrubs, glabrous to scabrous or hairy
Stems prostrate or decumbent to ascending or erect, < 3 m, ± striate below, minutely scabrous, yellow-white or gray to red-brown
Leaves alternate, sometimes clustered in axils, entire or toothed, gland-dotted, sometimes gummy, glabrous, minutely scabrous, or tomentose, light to dark gray-green
Inflorescence: heads discoid, in loose to tight clusters, these borne in flat-topped or ± spheric cymes; involucres obconic; phyllaries yellow-white below, texture cartilage-like, tips green; receptacles flat, naked
Flowers yellow; tubes narrowly cylindric, abruptly expanded into larger cylindric throat; sinuses shallow, lobes erect; style branch appendages triangular
Fruit narrowly obconic, light tan, silky-hairy; hairs white, yellow, tan, or light red-tan; pappus of 1–2 series of white, yellowish, or red-tan bristles ± 2 X fruit
Species in genus: ± 10 species: sw North America, Mex
Etymology: (Greek: equal hair-tuft, from flowers)
Reference: [Nesom 1991 Phytologia 70:69–114]


I. acradenia (Greene) Greene

Plant < 1.3 m, rounded or open
Stems erect or ascending, branched from ground or above, glabrous or minutely scabrous, yellow-white, varnished, shiny, becoming yellow-tan or gray with age
Leaves 1.5–6 cm, 1.5–15 mm wide, linear, obovate or spoon-shaped, entire or toothed, gland-dotted, glabrous or minutely scabrous, generally light gray-green
Inflorescence: heads in loose to tight clusters of 4–5; involucre 4–5 mm, 4–5 mm diam; phyllaries 22–36 in 3–6 series, oblong, tips blunt, rounded, or acute, green or tan to 1/4 total length of phyllary, swollen by glandular exudate below surface, appearing wart-like
Flowers 6–17
Fruit 2–3.5 mm; pappus 3–5.5 mm, white-yellow, bristles unequal
Chromosomes: 2n=12
Ecology: Sandy or clay soils in alkaline or gypsum flats or slopes
Elevation: < 1300 m.
Bioregional distribution: Tehachapi Mountain Area, San Joaquin Valley, South Coast Ranges, San Bernardino Mountains, Desert
Distribution outside California: Nevada, Arizona, Baja California
Synonyms: Haplopappus a. (Greene) S.F. Blake
Varieties intergrade somewhat.

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