Jepson Flora Project: Jepson Interchange    

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Jepson Interchange (more information)
©Copyright 1993 by the Regents of the University of California
For up-to-date information about California vascular plants, visit the Jepson eFlora.



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.


var. bracteosa (Greene) G.L. Nesom

Stems < 0.9 m
Leaves < 5 cm, much-reduced above, grading into bracts, sometimes toothed
Inflorescence: involucre closely subtended by bracts grading into phyllaries; phyllaries 25–36 in 4–6 series, tips blunt to acute (inner ones), abruptly soft-pointed
Flowers 10–17
Ecology: Sandy, alkaline soils
Elevation: < 900 m.
Bioregional distribution: San Joaquin Valley, Inner South Coast Ranges, nw Mojave Desert
Synonyms: Haplopappus a. subsp. b. (Greene) H.M. Hall

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bioregional map for ISOCOMA%20acradenia%20var.%20bracteosa being generated
YOU CAN HELP US make sure that our distributional information is correct and current. If you know that a plant occurs in a wild, reproducing state in a Jepson bioregion NOT highlighted on the map, please contact us with that information. Please realize that we cannot incorporate range extensions without access to a voucher specimen, which should (ultimately) be deposited in an herbarium. You can send the pressed, dried collection (with complete locality information indicated) to us (e-mail us for details) or refer us to an accessioned herbarium specimen. Non-occurrence of a plant in an indicated area is difficult to document, but we will especially value your input on those types of possible errors (see automatic conversion of distribution data to maps).

Retrieve Jepson Interchange Index to Plant Names entry for Isocoma acradenia var. bracteosa
Retrieve dichotomous key for Isocoma
Retrieve multiple-entry key (MEKA) for Isocoma
Overlay Consortium of California Herbaria specimen data by county on this map
Show other taxa with the same California distribution | Read about bioregions | Get lists of plants in a bioregion
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