Flowers axillary in clusters or solitary; perianth segments 6, divided to base, in 2 whorls. Male flowers with 6 glands at base of perianth segments representing the disc; stamens usually 3–5, filaments free or united. Female flowers with ovary 3- or more-locular; ovules 2 per loculus; styles 3, free or shortly fused, usually bifid.
Fruit mostly capsular, of three 2-valved fruitlets, dehiscent; seeds usually 3-angled.
| | Key to the species | |
| 1 | Branch leaves mostly scale-like (though plants of Phyllanthus lacunarius may have about half their branch leaves with well developed laminas) | 2 |
| Branch leaves with well-developed lamina or leaves reduced in size | 6 |
| 2 | Sepals 5, or if 6 then stamens 4–6 | 3 |
| Sepals 6 and stamens 3
Back to 1 | 4 |
| 3 | Branchlets flattened; stamens 3, filaments connate; female flowers solitary; styles notched; seeds striate | Phyllanthus amarus |
| Branchlets rounded; stamens 4–6, filaments free; female flowers 1–5; styles divided for half or more of their length
Back to 2 | Phyllanthus tenellus |
| 4 | Herbs, to 0.3 m high; stipules cream to yellow-brown; male sepals red; female pedicels at anthesis 0.2–1 mm long, in fruit 1–3 mm long; seeds striate | Phyllanthus lacunarius |
| Shrubs to 3 m high; stipules red-brown; male sepals white, yellow or green; female pedicels at anthesis 1.4–15 mm long, in fruit 2.2–18 mm long; seeds smooth, not striate
Back to 2 | 5 |
| 5 | Branchlets rounded, not ribbed, papillate; female pedicels 5–18 long; fruit 2.3–2.5 mm long | Phyllanthus microcladus |
| Branchlets angular to flattened, ribbed smooth; lamina convex to flat, with margins not thickened; male sepals smooth; female pedicels 2.2–5 mm long; fruit 1.8–2.2 mm long
Back to 4 | Phyllanthus similis |
| 6 | Plants monoecious; stipules 0.3–1.6 mm long, red to black; leaves 3–11 mm long | 7 |
| Plants dioecious; stipules 0.5–4.1 mm long, cream, red-brown or red; leaves 4.2–57.8 mm long
Back to 1 | 8 |
| 7 | Leaves usually flat with recurved margins, 1.8–6.6 mm wide, with long scattered hairs on the margins and the midvein; weak shrubs; mainly coastal and eastern parts of the tablelands | Phyllanthus hirtellus |
| Leaves usually revolute or strongly recurved, 0.5–3.5 mm wide, with a dense covering of short hairs; dense compact shrub; mainly western side of the tablelands and on the western slopes
Back to 6 | Phyllanthus occidentalis |
| 8 | Seeds distinctly granulate to tuberculate | 9 |
| Seeds rugose, striate or smooth
Back to 6 | 10 |
| 9 | Leaves 13.5–32.7 mm long, margins not thickened, veins slightly raised; female sepals in fruit 0.9–2 mm wide; filaments connate; styles notched | Phyllanthus maderaspatensis |
| Leaves 4.2–19.5 mm long, margins thickened, veins not raised; female sepals in fruit 0.3–0.7 mm wide; filaments free; styles divided for half or more of their length
Back to 8 | Phyllanthus virgatus |
| 10 | Plants densely hairy or at least glabrescent | 11 |
| Plants glabrous, rarely scabrous to papillose
Back to 8 | 12 |
| 11 | Branchlets rounded in cross section; stipules 0.5–1.7 mm long; male flowers 1–3 per axil; male pedicels 0.2–2 mm long; female sepals in fruit 1.6–5.5 mm long, 1–5.3 mm wide, enlarging and enclosing fruit; hilum not distictly bordered | Phyllanthus carpentariae |
| Branchlets elliptic to rounded in cross section; stipules 0.8–3.2 mm long; male flowers 1–7 per axil; male sepals glabrous to papillose; male pedicels 1.5–5.5 mm long; female sepals 1.1–3.6 mm long, in fruit 1–2.6 mm wide; not enlarging and enclosing fruit; hilum distinctly bordered
Back to 10 | Phyllanthus fuernrohrii |
| 12 | Branchlets ribbed | 13 |
| Branchlets not ribbed
Back to 10 | 15 |
| 13 | Branchlets rounded in cross section; stipules 0.6–1.4 mm long; leaves 5.5–18 mm long, with apex obcordate to emarginate; male pedicels 0.3–1 mm long; female pedicels 1.2–6.3 mm long; female pedicels in fruit 1–7.8 mm long; seeds with extra hilar depression | Phyllanthus lacunellus |
| Branchlets angular to flattened in cross section; stipules 1.1–5.2 mm long; leaves 6.6–57.8 mm long, apex acuminate to acute; male pedicels 1.2–6.3 mm long; female pedicels in fruit 1–7.8 mm long; seeds without extra-hilar depression
Back to 12 | 14 |
| 14 | Stipules cream to yellow-brown, with bases truncate to obtuse; leaves with veins slightly raised, margins smooth; female pedicels at anthesis 0.3–1.3 mm long; fruit 1.1–2.1 mm long; column 0.3–0.8 mm long; seeds 0.8–1.7 mm long | Phyllanthus lacerosus |
| Stipules red-brown, with bases cordate; leaves with veins not slightly raised, lamina, margins distinctly papillate; female pedicels at anthesis 1.5–4.5 mm long; fruit 2.8–3.4 mm long; column 1.9–4.2 mm long; seeds 2–2.7 mm long
Back to 13 | Phyllanthus subcrenulatus |
| 15 | Branchlets rounded in cross section; leaves linear to lanceolate and distinctly involute, 0.6–3.8 mm wide; male pedicels 0.4–2 mm long | Phyllanthus involutus |
| Branchlets flattened, ellipsoid or rounded in cross section; leaves elliptic, circular, obovate or oblanceolate, flat, 2.6–20 mm wide; male pedicels 0.8–6 mm long
Back to 12 | 16 |
| 16 | Shrubs to 2.5 m high; stipule apices obtuse to rounded; styles undivided; hilum markedly depressed or bordered | Phyllanthus gunnii |
| Low shrubs or herbs to 0.4 m high; stipule apices acute to acuminate; styles variously divided; hilum markedly depressed and bordered
Back to 15 | Phyllanthus oblanceolatus |
