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.

RUMEX

DOCK

Annual, biennial, perennial herb, generally from stout taproot, some dioecious, glabrous
Stem generally erect, generally unbranched below inflorescence, < 2 m, ± ridged, generally red-brown in fruit; nodes ± swollen
Leaves generally ± basal, alternate, petioled; stipules fused, sheathing stem above nodes, fracturing; blade < 50 cm
Inflorescence: bracted clusters generally arrayed in erect panicles
Flower generally bisexual, < 3 mm, generally green; perianth lobes 6, persistent, outer 3 in fruit ± inconspicuous, inner 3 in fruit enlarged, hardened, ± veiny, covering fruit, midrib often expanded into a tubercle; stamens 6; stigmas 3, fringed
Fruit brown, shiny
Etymology: (Latin: sorrel)
Reference: [Mitchell 1978 Brittonia 30:293–296]
Hybrids common. Mature inner perianth lobes generally required for identification. Some cultivated for vegetable greens. TOXIC in quantity to livestock; seldom eaten.

Native

R. salicifolius Weinm.

WILLOW DOCK

Perennial
Stem prostrate to ± erect, < 1 m; branches from most nodes often producing flowers later than main axis
Leaves cauline, generally crowded below, 3–20 cm; blade linear to ovate, margin entire, flat or ± curled
Inflorescence dense to open
Flower: inner perianth lobe 2–5 mm, narrowly ovate to ± round, teeth generally 0, tubercles variable
Fruit 2–3 mm
Ecology: Common. Moist places
Elevation: 0–3500 m.
Bioregional distribution: California
Distribution outside California: to Alaska, e N.America, Mexico, naturalized in Europe
Reference: [Hickman 1984 Madroño 31:249–252]
Highly variable, even within plants; intergrading complex, warrants detailed study.

Native

var. lacustris (Greene) J.C. Hickman

Stem ± decumbent if terrestrial, erect and emergent if aquatic
Leaf: blade generally widely lanceolate, some elliptic or oblong, ± thickened
Inflorescence dense, continuous, ± 5 cm
Flower: inner perianth lobe 2–5 mm, tubercles 3, generally << 1/3 width of lobe, narrowly lanceolate, ± equal
Ecology: Beds, shores of ± salty lakes
Elevation: 1000–2500 m.
Bioregional distribution: Great Basin Floristic Province (especially Modoc Plateau)
Distribution outside California: s Oregon, Nevada
Flowering time: Jul–Sep
Synonyms: R. l. Greene
Growth form variable with water level: emergent plants generally unbranched, leafless below initial water level
Horticultural information: TRY; STBL.