EUPHORBIACEAE

SPURGE FAMILY

Grady L. Webster, except as specified

Annual, perennial herb, shrub, tree, vine, monoecious or dioecious
Stem generally branched, sometimes fleshy or spiny
Leaves generally simple, alternate or opposite, generally stipuled, petioled; blade entire, toothed, or palmately lobed
Inflorescence: cyme, panicle, raceme, spike; flowers sometimes in clusters (dense, enclosed by involucre, flower-like in Chamaesyce, Euphorbia ), terminal or axillary
Flower unisexual, ± radial; sepals generally 3–5, free or fused; petals generally 0; stamens 1–many, free or filaments fused; ovary superior, chambers 1–4, styles free or fused, simple or lobed
Fruit: generally capsule
Seeds 1–2 per chamber; seed scar appendage sometimes present, pad- to dome-like
Genera in family: 300 genera, 7500 species: ± worldwide especially tropical; some cultivated (Aleurites , tung oil; Euphorbia subsp.; Hevea , rubber; Ricinus )
Reference: [Webster 1967 J Arnold Arbor 48:303–430]
Many species ± highly TOXIC.

CHAMAESYCE

PROSTRATE SPURGE

Daryl L. Koutnik

Annual, perennial herb, generally monoecious, glabrous to hairy; sap milky
Stem prostrate to erect, < 5 dm; branches alternate
Leaves cauline, opposite, short-petioled; stipules present; blade base generally asymmetric, veins dark green
Inflorescence flower-like, generally 1 per node; involucre ± bell-shaped, bracts 5, fused; glands 4, distal appendages generally colorful, petal-like; flowers central
Staminate flowers 3–many, generally in 5 clusters around pistillate flower, each flower a stamen
Pistillate flower 1, central, stalked; ovary chambers 3, ovule 1 per chamber, styles 3, separate or fused at base, divided to entire
Fruit: capsule, round to 3-angled or -lobed in X -section
Seed generally 4-angled, smooth or sculptured
Species in genus: ± 250 species: dry temp, subtropical worldwide, especially Am. Often treated as subg. of Euphorbia
Etymology: (Greek: ancient name for kind of prostrate plant)
Reference: [Wheeler 1941 Rhodora 43:97–154, 168–286]
Horticultural information: STBL.

Native

C. hooveri (L.C. Wheeler) Koutnik

HOOVER'S SPURGE

Annual
Stem prostrate to decumbent, glabrous
Leaf 2–5 mm; stipules fused, fringed; blade round, glabrous, papillate, tip rounded, margin coarsely toothed
Inflorescence: involucre ± 2 mm, bell-shaped, glabrous; gland < 1 mm, round; appendage wider than gland, deeply 3–5-lobed, white
Staminate flowers 30–35
Pistillate flower: style undivided
Fruit 1.5–2 mm, spheric, lobed, glabrous
Seed ± 1.5 mm, ovoid, widely 4-angled, shallowly ridged, white
Ecology: Vernal pools
Elevation: < 250 m.
Bioregional distribution: Great Central Valley (Butte, Tehama, Tulare cos.)
Synonyms: Euphorbia h. L.C. Wheeler
Threatened by habitat loss.