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.

SYSTENOTHECA

Species in genus: 1 sp
Etymology: (Greek: tapering case, from involucre)
Reference: [Reveal & Hardham 1989 Phytologia 66:83–88]

Native

S. vortriedei (Brandegee) Reveal & Hardham

VORTRIEDE'S SPINEFLOWER

Annual, spreading, 2–15 cm, glandular
Leaves basal; stipule 0; petiole indistinct; blade 20–50 mm, tongue-shaped to oblanceolate, glabrous
Inflorescence open, 5–30 cm diam; bract 1 per node, 1–5 mm, deeply 3–4-lobed, awned, lower bracts encircling stem; involucre 1 per node, generally 4–5 mm, cylindric and box-like, lobes 4, awned; flowers 1 each of 2 types per involucre
Flowers: 1 bisexual, exserted, perianth generally reddish; 1 sterile or pistillate, included, perianth white; in both types perianth glabrous, lobes 6, tips notched; stamens 9
Fruit 2–2.5 mm, dark brown to black
Ecology: UNCOMMON. Woodland, on sand or serpentine
Elevation: 700–1600 m.
Bioregional distribution: Outer South Coast Ranges (Santa Lucia Mtns, Monterey, San Luis Obispo cos.)
Synonyms: Chorizanthe v. Brandegee; Centrostegia v. (Brandegee) Goodman
Horticultural information: DRN, SUN: 7, 14, 15, 16, 17.