Description: Trees or shrubs, mostly pubescent, dioecious.
Leaves alternate, entire or shallowly crenate, petiole short.
Flowers in axillary clusters, paired or solitary, shortly pedunculate. Male flowers with 4–6 perianth segments, small, stamens 20–40 borne on a short column. Female flowers with 4–8 perianth segments, the outer whorl longer and narrower than the inner; ovary 3–4-locular, 2 ovules in each loculus; styles large, often petaloid, not persistent.
Capsule globose, grooved, usually orange, with a fleshy exocarp and a woody endocarp, splitting at maturity; seeds glossy, ± oblong, with a small caruncle.
Distribution and occurrence: World: 7 species, Australia & New Guinea. Australia: 6 species, Qld, N.S.W., N.T., W.A., mainly tropical & extending into arid areas.
Petalostigma was formerly placed in Euphorbiaceae.
Text by T.A. James & G.J. Harden, Flora of New South Wales Vol. 1: 401-402 (1990), in Euphorbiaceae; revised May 2017
Taxon concept: Australian Plant Census (accessed May 2017)
| | Key to the species | |
| 1 | Leaves more than 2.5 times as long as wide, narrow-elliptic, mostly 5–9 cm long, acute at apex and often at base also, usually drying dark brown above; capsule more or less glabrous, mostly 3-locular | Petalostigma triloculare |
| Leaves less than 2.5 times as long as wide, ovate to more or less circular, mostly 2–5 cm long, apex often obtuse, rarely drying dark brown above; capsule pubescent, mostly 4-locular | Petalostigma pubescens |
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