Jepson Flora Project: Jepson Interchange    

 
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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.

OXYTHECA

Annual, glandular, glaucous
Leaves basal; stipule 0; petiole indistinct; blade linear to obovate, hairy
Inflorescence open; bracts generally 3 per node, generally linear-lanceolate, generally fused at base, awned; involucre 1 per node, generally stalked, narrowly funnel-shaped to bell-shaped, teeth 3–36, awned; flowers 2–20 per involucre
Flower: perianth white to rose or pale yellow, hairy, lobes 6; stamens 9
Fruit golden-brown to dark brown. w North America., s South America
Etymology: (Latin: sharp box, from involucre)
Reference: [Ertter 1980 Brittonia 32:70–102]

Native

O. watsonii Torr. & A. Gray

WATSON'S OXYTHECA

Plant 5–25 cm
Leaf 0.7–5 cm, oblanceolate to obovate, generally sparsely strigose and glandular
Inflorescence glandular at or near nodes; bract awns 1–3 mm; involucre narrowly funnel-shaped, glabrous, involucral bracts 4, 1.5–2 mm, ± half fused (except awns), awns 2.5–3 mm; flowers 2–7 per involucre
Flower: perianth 1–1.5 mm, greenish white to pink, hairy; lobes entire
Fruit 1–1.5 mm
Chromosomes: n=20
Ecology: Sandy places
Elevation: 1200–2000 m.
Bioregional distribution: se White and Inyo Mountains (Santa Rosa Hills, Inyo Co.)
Distribution outside California: Nevada
Flowering time: May–Jul
Name misapplied to O. parishii var. goodmaniana.
See the CNPS Inventory for information about endangerment and rarity.
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bioregional map for OXYTHECA%20watsonii being generated
 


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