Excoecaria L.

Euphorbiaceae, A. R.-Smith. Flora of Tropical East Africa. 1987

Morphology General Habit

Dioecious or monoecious completely glabrous trees, shrubs or subshrubs

Morphology Leaves

Leaves alternate or opposite, petiolate, stipulate, simple, entire, crenulate or serrulate, penninerved, eglandular at the base of the lamina

Morphology Reproductive morphology Inflorescences

Inflorescences axillary, terminal or occasionally leaf-opposed, spicate or racemose, solitary or fascicled, unisexual or bisexual, if the latter then with most of the inflorescence ♂ with 1–5 ♀ flowers at the base; ♂ bracts 1–many-flowered, small, each biglandular at the base; bracteoles present or 0

sex Male

Male flowers small, sessile or subsessile; sepals (2–)3(–4), free or united at the base, imbricate; petals 0; disc 0; stamens (2–)3(–8), free, anthers extrorse, basifixed, 2-thecous, the thecae free at the base, longitudinally dehiscent; pistillode 0

Morphology Reproductive morphology Flowers

Female flowers small, shortly pedicellate; sepals (2–)3, free or united, imbricate; petals 0; disc 0; ovary (2–)3-locular, with 1 ovule per locule; styles (2–)3, free or slightly connate at the base, entire, strongly coiled Male flowers small, sessile or subsessile; sepals (2–)3(–4), free or united at the base, imbricate; petals 0; disc 0; stamens (2–)3(–8), free, anthers extrorse, basifixed, 2-thecous, the thecae free at the base, longitudinally dehiscent; pistillode 0

sex Female

Female flowers small, shortly pedicellate; sepals (2–)3, free or united, imbricate; petals 0; disc 0; ovary (2–)3-locular, with 1 ovule per locule; styles (2–)3, free or slightly connate at the base, entire, strongly coiled

Morphology Reproductive morphology Fruits

Fruit (2–)3-lobed, dehiscing into (2–)3 bivalved cocci, the valves of which then separate and coil up; exocarp smooth, not separating from the endocarp; endocarp thinly crustaceous; columella persistent, 3-winged at the apex

Morphology Reproductive morphology Seeds

Seeds globose or ovoid; caruncle (? swollen funicle) separating from the seed and remaining adnate to the columella; testa crustaceous; albumen fleshy; cotyledons broad, flat.

M. Thulin et al. Flora of Somalia, Vol. 1-4 [updated 2008] https://plants.jstor.org/collection/FLOS

Morphology General Habit

Dioecious or monoecious glabrous trees, shrubs or subshrubs

Morphology Leaves

Leaves alternate or opposite, simple; petioles without glands; stipules present

Morphology Reproductive morphology Inflorescences

Flowers small, in spikes or racemes

Morphology Reproductive morphology Flowers

Female flowers shortly pedicellate; sepals (2–)3; petals and disc absent; ovary (2–)3-celled with 1 ovule per cell; styles (2–)3, entire Male flowers sessile or subsessile; sepals (2–)3(–4), imbricate; petals absent; stamens (2–)3(–8), free; disc and pistillode absent

Morphology Reproductive morphology Fruits

Fruit dehiscing into (2–)3 bivalved cocci, the valves of which then separate and coil up

Morphology Reproductive morphology Seeds

Seeds globose or ovoid, with caruncle separating from the seed and remaining adnate to the persistent columella of the fruit.

Distribution

Some 35-40 species in the tropics of the Old World.

Timothy M. A. Utteridge and Laura V. S. Jennings (2022). Trees of New Guinea. Kew Publishing. Royal Botanic Gardens, Kew

Morphology General

Latex present in all parts

Morphology General Indumentum

Indumentum lacking

Morphology Leaves Stipules

Stipules small, caducous

Morphology Leaves

Leaves alternate or opposite, margins entire or serrulate, penninerved; petiole short, with basally 2 glands in the margin at either side of the petiole insertion

Morphology General Habit

Plants monoecious or dioecious (E. agallocha) Shrubs or trees to 30 m

Morphology Reproductive morphology Inflorescences

Inflorescences axillary or terminal, racemose or spicate-like thyrses, usually unisexual or staminate inflorescences with 1–few pistillate flowers at the base

Morphology Reproductive morphology Flowers

Flowers lacking petals, disk absent. Staminate flowers (sub)sessile; sepals 2–3, small, imbricate, free or shortly connate; stamens 3, anthers longitudinally dehiscent, filaments free; pistillode absent

Morphology Reproductive morphology Flowers Gynoecium Pistil

Pistillate flowers sessile to pedicellate; sepals 3, free or connate; ovary 3-celled, smooth; stigmas extended or recurved, free to slightly connate at base, undivided

Morphology Reproductive morphology Fruits

Fruit a 3-locular capsule, dehiscing into 2-valved cocci; columella persistent, winged

Morphology Reproductive morphology Seeds

Seeds globose or oblong, carcuncle usually lacking.

Distribution

Excoecaria agallocha is a common tree found in mangrove edges and various swampy habitats (including freshwater swamp forest, sago swamp and Melaleuca swamp), or primary forest and mangrove transition to 60 m; E. myrioneura has been collected from primary and secondary forest up to 220 m. A genus of c. 35 species: Africa, Asia, Australia, Pacific islands; two species in New Guinea: Excoecaria agallocha L. and E. myrioneura Airy Shaw.

Recognition

The genus can be recognised by the tree habit, no indumentum, the milky latex in all parts, the simple leaves, the racemose or spicate inflorescences (especially so in the staminate inflorescences), flowers lacking petals, and the dehiscent fruits.