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	©Copyright 1993 by the Regents of the University of California Print edition is available from the University of California Press

	The second edition of The Jepson Manual (2012) is available from the University of California Press
	See also the Jepson eFlora, which parallels the Second Edition

POLYGONACEAE

BUCKWHEAT FAMILY

James C. Hickman

Annual to trees, some dioecious
Stem: nodes often swollen
Leaves simple, basal or cauline, alternate, opposite, or whorled, generally entire; stipules 0 or obvious and fused into a generally scarious sheath around stem
Inflorescence: small cluster, axillary or arrayed in cymes or panicles; involucres sometimes subtending 1–many flowers
Flower generally bisexual, small, ± radial; perianth generally 5–6-lobed, base ± tapered, often jointed to pedicel; stamens 2–9, often in 2 whorls; ovary superior, styles generally 3, generally fused at base
Fruit: achene, generally enclosed by persistent perianth, generally 3-angled, ovoid, and glabrous
Genera in family: 50 genera, 1100 species: worldwide, especially n temp; some cultivated for food (Fagopyrum ; Rheum , rhubarb; Rumex , sorrel) or ornamental (Antigonon , coral-vine; Muehlenbeckia ; Polygonum )
Reference: [Ronse Decraene & Akeroyd 1988 Bot J Linn Soc 98:321–371; Reveal et al. 1989 Phytologia 66(2–4):83–414]
Treatments of the 15 eriogonoid genera are based on the monographic work of James L. Reveal, who is gratefully acknowledged.

ERIOGONUM

WILD BUCKWHEAT

Annual to shrub
Leaves generally ± basal (clustered on low stems or cauline), petioled, generally ± tomentose below (often shedding above); stipule 0
Inflorescence openly cyme-like, umbel-like, or head-like, generally ± scapose; bracts (any whorled, leaf-like structures on inflorescence) 3–many per node, leaf-like to scale-like; involucres generally 1 per node, generally ± obconic, lobes (or short teeth) generally 3–10, generally erect; flowers generally many per involucre, pedicelled
Flower: perianth white, yellow, or red, lobes 6, generally ± oblong to obovate; stamens 9
Fruit brown to black, glabrous to hairy
Species in genus: ± 250 species: North America
Etymology: (Greek: woolly knees, from hairy nodes of some)
Reference: [Reveal 1989 Phytologia 66:295–414]
Largest dicot genus in CA; apparently currently differentiating; many taxa ± indistinct. Better habitat data needed. Many are excellent bee fodder
Horticultural information: Most are attractive and easy to grow with good drainage.

Native

E. spergulinum A. Gray

[Group 2] Annual 5–40 cm
Leaves basal; blade 3–30 mm, linear (< 2 mm wide), ciliate
Inflorescence cyme-like, prostrate to erect, slender; involucres on ± erect, thread-like stalks, 0.5–1 mm, unribbed, glabrous, teeth 4
Flower: perianth 1–3 mm, white, striped darker
Fruit ± 2 mm, glabrous
Ecology: Dry sand (especially granitic)
Elevation: 1200–3500 m.
Bioregional distribution: High North Coast Ranges, High Cascade Range, Sierra Nevada, n Outer South Coast Ranges, Transverse Ranges, Great Basin Floristic Province
Distribution outside California: to Oregon, Idaho, Nevada
Varieties indistinct, intergrading.

Native

var. reddingianum (M.E. Jones) J.T. Howell

Inflorescence erect, 8–40 cm; axes glandular
Flower: perianth ± 2 mm
Ecology: Common. Sand or gravel
Elevation: 1400–3500 m.
Bioregional distribution: High North Coast Ranges, High Cascade Range, Sierra Nevada, n Outer South Coast Ranges, Transverse Ranges, Great Basin Floristic Province
Distribution outside California: to Oregon, Idaho, Nevada
Flowering time: Jun–Aug