Description: Shrubs or small to large trees, with simple hairs, unarmed.
Leaves opposite, 1-foliolate or palmately 3-foliolate; leaflets with margins entire.
Inflorescences axillary, cymose or paniculate [or reduced to 1 flower]. Flowers bisexual, 4-merous. Sepals 4, free or basally fused. Petals 4, valvate, free, narrow-triangular to sublanceolate, becoming reflexed, persistent or not persistent in fruit. Stamens 8, free, divergent. Ovary 4-locular or rarely to 8-locular, with or without fissures between the locules, ± pyramidal; styles fused, arising terminally from ovary; stigma scarcely differentiated from style; ovules 2 in each loculus.
Fruit a 4-loculate (or rarely 4- to 8-loculate) drupe, with or without septicidal fissures, or rarely comprised of 4 ascending, beaked follicle-like carpels; epicarp drying semifleshy or rarely papery, or the mesocarp spongy-crustaceous to woody; seeds dull to shiny, black.
Distribution and occurrence: World: 44 spp., India, S Asia, Malesia & Pac.Is. Aust.: 19 spp. (16 spp. endemic), Qld, N.S.W., Vic.
Text by P.G. Richards & G.J Harden
Taxon concept:
| | Key to the species | |
| 1 | Leaves mostly 3-foliolate (rarely occasional leaves 1-foliolate). | 2 |
| Leaves 1-foliolate. | 4 |
| 2 | Leaflets usually 8–20 cm long, glabrous or finely hairy, with 10–20 pairs of main lateral veins; petioles without raised corky bands. | 3 |
| Leaflets mostly 4–8.5 cm long, glabrous, with 7–11 pairs of main lateral veins ; petioles of older leaves often encircled with raised corky bands.
Back to 1 | Acronychia suberosa |
| 3 | Leaflets glabrous, with 16–20 pairs of main lateral veins; fruit comprised of 4 ascending, beaked carpels, connate only at base. | Acronychia octandra |
| Leaflets hairy on lower surface, at least on midrib and veins, with 10–13 pairs of main lateral veins; fruit drupaceous, comprised of 4 erect, ± fused carpels, not beaked.
Back to 2 | Acronychia pubescens |
| 4 | Stems, lower surface of leaves and inflorescences distinctly hairy. | Acronychia pubescens |
| Stems, lower surface of leaves and inflorescences ± glabrous or rarely obscurely hairy.
Back to 1 | 5 |
| 5 | Oil dots absent or ± invisible in leaves, sometimes translucent blotches or streaks present; fruit yellow to yellow-orange. | Acronychia imperforata |
| Oil dots present in leaves, translucent and conspicuous; fruit white, creamy white or mauve.
Back to 4 | 6 |
| 6 | Petioles of young leaves at least finely hairy on upper surface; larger inflorescences <2 cm long; lower surface of leaves sometimes very sparsely and minutely hairy. | Acronychia pauciflora |
| Petioles of young leaves glabrous; larger inflorescences >2 cm long; lower surface of leaves glabrous.
Back to 5 | 7 |
| 7 | Petioles 1.2–2.2 mm wide; fruit 4–8-carpellate and 4–8-lobed. | 8 |
| Most petioles <1.2 mm wide; fruit 4-carpellate and 4-lobed.
Back to 6 | 9 |
| 8 | Oil dots in leaves moderately numerous to sparse, faintly to moderately translucent; fruit 4-lobed, glabrous, shallowly apically fissured to less than halfway; leaves strongly spicy-aromatic when crushed. | Acronychia littoralis |
| Oil dots in leaves numerous and usually dense, strongly translucent;fruit 4–8-lobed (always some 5–8-lobed fruit present), with apical tuft of hairs, deeply fissured to more than halfway between carpels when dry, sometimes carpels fully separating in fruit; leaves not strongly aromatic when crushed.
Back to 7 | Acronychia wilcoxiana |
| 9 | Fruit mauve, drying to reddish black; leaves glossy on both surfaces. | Acronychia laevis |
| Fruit white to greenish white or cream-coloured; leaves not glossy or glossy on upper surface only.
Back to 7 | 10 |
| 10 | Petals 9–13 mm long; leaves ± elliptic, with 10–13 pairs of main lateral veins; fruit ± ovoid, 9–15 mm diam., sharply and deeply 4-angled when dry, glabrous. | Acronychia baeuerlenii |
| Petals 5–7 mm long; leaves ± obovate, with 5–11 pairs of main lateral veins; fruit globose to depressed-globose, 8–12 mm diam., shallowly 4-lobed when dry, with apical tuft of hairs.
Back to 9 | Acronychia oblongifolia |
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