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Jepson Interchange (more information)
©Copyright 1993 by the Regents of the University of California

  • Up-to-date information about California vascular plants is available from 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.


David J. Keil and Gregory K. Brown

Annual to subshrubs
Stems from taproot or ± branched caudex
Leaves simple, alternate, entire to pinnately dissected; teeth or lobes often ± bristle-tipped
Inflorescence: heads radiate or discoid, solitary or cymosely clustered; involucre bell-shaped, hemispheric, or obconic; phyllaries in 2–several series of unequal length, basal portion straw-colored to purplish, tips green; receptacle convex, naked or with short, triangular scales (not chaff)
Ray flowers 8–many; corollas yellow, white, pink, blue, or purple
Disk flowers 10–many; corollas yellow; style tips triangular to linear, acute
Fruit linear to club-shaped or obovoid, smooth or several–many-ribbed, glabrous to densely hairy; pappus of many unequal bristles (ray pappus sometimes 0)
Species in genus: ± 35 species: temp w North America
Etymology: (Greek: sword-like anthers)
Reference: [Hartman 1990 Phytologia 68:439–465]


M. arida B.L. Turner & D.B. Horne


Stems branched from base, 5–30 cm, glandular with nonglandular hairs interspersed
Leaves generally sessile, 1–30 mm, 1–10 mm wide, oblong, toothed to pinnately lobed; lobes and teeth bristle-tipped; upper leaves reduced, appressed
Inflorescence: heads radiate, solitary or in cymes; involucre 3–6 mm, 5–10 mm wide, hemispheric; phyllaries in 2–3 series, oblong to oblanceolate, glandular
Ray flowers 25–35, < or = 7 mm, white to lavender
Disk flowers 28–45, 2.5–3 mm
Fruit 1.4–1.9 mm, hairy; ray pappus 0 or obscure; disk pappus of many bristles, 2–3 mm, white
Chromosomes: 2n=10
Ecology: Uncommon. Riverbanks, sandy, alkaline flats, roadsides
Elevation: 30–300 m.
Bioregional distribution: Desert
Distribution outside California: s Nevada, s Arizona, n Mexico
Flowering time: Mar–Jun
Synonyms: Psilactis coulteri A. Gray misapplied

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