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. breedlovei (J.T. Howell) Reveal

[Group 4] Perennial generally < 10 cm; mats 8–20 cm diam
Leaves ± basal on branched caudex; blade 2–10 mm, elliptic, white-woolly below, gray-tomentose above
Inflorescence densely umbel-like, sometimes ± compound; bracts scale-like; involucres ± few, slender-stalked, 2.5–4 mm, rigid, angled, teeth 7–9, becoming incurved
Flower: perianth 2–4 mm, whitish to reddish, ± hairy, stalk-like base 0
Fruit 2–3 mm, glabrous
Ecology: Granite or limestone
Elevation: 1700–2500 m.
Bioregional distribution: s High Sierra Nevada.Much like E. kennedyi.

Native

var. shevockii J.T. Howell

THE NEEDLES BUCKWHEAT

Inflorescence dense to open, generally ± glabrous; involucre teeth rounded, obviously scarious-margined
Ecology: UNCOMMON. Granite
Elevation: 1700–2500 m.
Bioregional distribution: s High Sierra Nevada (The Needles, Baker Point, Little Kern River gorge, Kern and Tulare cos.).