Inflorescences an aggregation of axillary flowers at apex of shoot subtended by green or coloured bracts. Flowers 5-merous, each flower enclosed by 2 bracteoles when in bud. Sepals usually small, ± petaloid. Petals white, usually enclosing lower part of style. Stamens 10, alternating with 10 staminodes; anthers globose, opening by terminal pores. Ovary half-inferior, 1-locular; placenta basal; ovules 2–10; style projecting from flower, bearing a group of hairs below stigma.
| | Key to the species | |
| 1 | Leaves laterally compressed, keeled | 2 |
| Leaves terete or nearly so. | Darwinia fascicularis |
| 2 | Bracteoles extending beyond perianth; style recurved, with hairs in a lateral tuft | Darwinia taxifolia |
| Bracteoles shorter than perianth; style straight or curved, hairs usually in a ring
Back to 1 | 3 |
| 3 | Sepals more than three-quarters the length of petals; hypanthium papillate between ribs | 4 |
| Sepals less than three-quarters the length of petals; hypanthium smooth between ribs (rarely slightly papillate in D. leptantha)
Back to 2 | 5 |
| 4 | Hypanthium 7–12 mm long; style 12–20 mm long | Darwinia grandiflora |
| Hypanthium 3–5 mm long; style 4–9 mm long
Back to 3 | Darwinia diminuta |
| 5 | Flowers, including style, 4–9 mm long; bracteoles yellow-green or yellow-brown | 6 |
| Flowers, including style, 9–25 mm long; bracteoles dark brown or red-purple
Back to 3 | 8 |
| 6 | Hypanthium 1–2 mm diam., bracteoles 3.5–6 mm long, persisting until after anthesis | 7 |
| Hypanthium more or less 0.5 mm diam., bracteoles 2–3.5 mm long, caducous
Back to 5 | Darwinia leptantha |
| 7 | Hypanthium glabrous between the broad or rounded longitudinal ribs. | Darwinia camptostylis |
| Hypanthium papillose between the distinct narrow ribs.
Back to 6 | Darwinia briggsiae |
| 8 | Hypanthium ± 1.5 mm diam., with distinct glaucous ridges | 9 |
| Hypanthium 1.5–2.5 mm diam., ribs obscure or broad and rounded
Back to 5 | 10 |
| 9 | Leaves glaucous, 8–17 mm long; bracteoles red-brown, caducous | Darwinia glaucophylla |
| Leaves green, 6–10 mm long; bracteoles purple-red, persisting till after anthesis
Back to 8 | Darwinia biflora |
| 10 | Peduncles 4–7 mm long; style 6–10 mm long | Darwinia peduncularis |
| Peduncles 1–2 mm long; style 14–20 mm long
Back to 8 | Darwinia procera |
