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.

TETRACOCCUS

Shrub, generally 0.5–2 m, dioecious; sap clear
Stem: axis erect; branches generally many, spreading to erect; twigs generally reddish, becoming gray, generally hairy, becoming glabrous; young lateral twigs short, sometimes becoming spine-like
Leaves simple, cauline, alternate, opposite, or whorled in 3's, generally clustered at short, lateral branch tips; stipules 0; petiole < 2 mm; blade leathery, entire or toothed, base obtuse to acute
Staminate inflorescence: cyme, raceme, or panicle, axillary, sometimes clustered on short, lateral twigs, minutely bracted
Pistillate inflorescence axillary; flower 1
Staminate flower: sepals 4–10, 0.5–2 mm; petals 0; stamens 5–10, filaments glabrous or hairy; nectary disk ± minutely lobed
Pistillate flower: sepals 4–13, 2–5 mm; petals 0; nectary disk minutely lobed; ovary (2)3–5-chambered, styles = chambers, free, ± flattened, generally spreading
Fruit ± spheric, generally lobed, glabrous or short hairy, generally brown
Seeds 1–2 per chamber, smooth, shiny; scar generally appendaged
Species in genus: 5 species: CA, AZ, Mex
Etymology: (Latin: 4 seeds, from 4-lobed ovary in T. dioicus )
Reference: [Dressler 1954 Rhodora 56:45–61]

Native

T. ilicifolius Coville & Gilman

HOLLY-LEAVED TETRACOCCUS

Stem: twigs sparsely and finely brown-tomentose, becoming glabrous
Leaves generally opposite or 3-whorled; blade 15–30 mm, ovate to widely elliptic, sometimes narrowly ovate, tip obtuse to acute, margin toothed, teeth 8–20 per leaf
Staminate inflorescence: panicle, ± dense; flowers ± sessile; pedicel << 0.5 mm
Staminate flower: sepals 7–9, ± linear to lanceolate; stamens 7–9, filaments 2–3 mm, base soft-hairy
Pistillate flower: pedicel 8–15 mm; sepals 5–8, 2–4 mm, widely lanceolate to ovate; ovary densely tomentose, chambers 4, style ± 3 mm
Fruit 8–9 mm, 6–8 mm wide, brown tomentose
Ecology: Dry, rocky slopes
Elevation: 600–1700 m.
Bioregional distribution: n Desert Mountains (Grapevine, Panamint mtns)
Flowering time: May–Jun
Horticultural information: In cultivation.