Leaves alternate or opposite, margins entire, regularly toothed or deeply lobed.
Inflorescences indeterminate, spike-like. Flowers mostly 4-merous, on short pedicels. Sepals and petals 2, 3 or 4. Stamens twice as many as the sepals; filaments short; anthers not apiculate. Ovary mostly 4-locular; styles equal in number to the loculi.
| | Key to the species | |
| 1 | Margins of leaves entire or toothed | 2 |
| Leaves variously lobed, pinnatifid, trifid or multifid with more or less palmate divisions | 8 |
| 2 | Leafy stems more or less square in cross section and distinctly 4-ribbed, leaves usually opposite until inflorescence | 3 |
| Stems smooth to weakly 4-ribbed; leaves usually opposite only at the base of the plant
Back to 1 | 5 |
| 3 | Ovary 4-locular, styles 4 | 4 |
| Ovary 2-locular, styles 2
Back to 2 | Haloragis serra |
| 4 | Leaves ± 5 mm wide | Haloragis exalata |
| Leaves mostly 2–4 mm wide
Back to 3 | Haloragis stricta |
| 5 | Robust subshrub to 1.2 metres; leaves > 16 mm wide | Haloragis milesiae |
| Annual or perennial herb to 0.5 metres; leaves 10–15 mm wide
Back to 2 | 6 |
| 6 | Leaves with a distinct petiole 5–15 mm long | Haloragis odontocarpa |
| Leaves sessile or very shortly petiolate
Back to 5 | 7 |
| 7 | Leaves and stems glaucous, glabrous or scabrous with curved hairs | Haloragis glauca |
| Leaves and stems grey-green, scabrous with hooked hairs
Back to 6 | Haloragis aspera |
| 8 | Leaves pinnatifid | Haloragis aspera |
| Leaves below inflorescences trifid or multifid with more or less palmate divisions
Back to 1 | Haloragis heterophylla |
