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

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

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. wrightii Benth.

[Group 4] Perennial to shrub, 15–100 cm, 10–150 cm diam
Leaves cauline or clustered on low stems; blade 1–30 mm, linear to widely elliptic, generally densely tomentose (especially below)
Inflorescence cyme- to head-like; branches long, wand-like, glabrous to densely woolly; bracts scale-like; involucres sessile (most lateral), 1–4 mm, glabrous to densely woolly, teeth 5
Flower: perianth 1.5–4 mm, white to pink or rose, glabrous, lobes obovate, stalk-like base 0
Fruit 1–3 mm, glabrous
Ecology: Dry gravel or rocks
Elevation: 50–3500 m.
Bioregional distribution: Northwestern California, s Cascade Range, Sierra Nevada, Central Western California, Southwestern California, White and Inyo Mountains, Desert
Distribution outside California: to s Nevada, Texas, Mexico
Variable; vars. intergrade.

Native

var. nodosum (Small) Reveal

Shrub 30–100 cm, 30–150 cm diam, densely gray-woolly
Leaf: blade 8–12 mm, ± flat
Inflorescence open; branches stout; involucre 1.5–2.5 mm
Flower: perianth 3–4 mm
Fruit 2.5–3 mm
Ecology: Uncommon. Dry gravel or rocks
Elevation: 150–1600 m.
Bioregional distribution: eastern Peninsular Ranges, s-most Mojave Desert, w Sonoran Desert
Distribution outside California: n Baja California

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