Flowers usually axillary, solitary. Epicalyx segments 5 or more, free or fused. Calyx 5-lobed. Petals mostly showy with a darker basal spot. Staminal column truncate or 5-toothed at summit with numerous filaments. Ovary 5-locular with usually >3 ovules in each loculus; style branches 5, spreading; stigmas capitate.
Many species are cultivated as ornamentals, resulting in isolated records of some native species outside their natural range. H. cannabinus L. is being grown experimentally in Australia for paper pulp and associated products. H. insularis Endl. is considered endangered on Phillip I. (near Norfolk I.). H. mutabilis L., the Confederate Rose, was erroneously listed as naturalized in Jacobs & Pickard (1981). Ref. Wilson (1974).
| | Key to the species | |
| 1 | Annual herb or short-lived perennial; calyx membranous and inflated after flowering | 2 |
| Trees, shrubs or subshrubs; calyx neither membranous nor inflated after flowering | 4 |
| 2 | Mid-stem and distal leaves lobed to the apex of the petiole; pedicel 0.25–0.6mm long | Hibiscus tridactylites |
| Mid-stem and distal leaves not lobed to the apex of the petiole; pedicel 4–20mm long
Back to 1 | 3 |
| 3 | Seed glabrous, 2.5–2.8mm long; style branches 0.6–1 mm long | Hibiscus verdcourtii |
| Seed hairy, 2.0–2.6mm long; style branches 2.3–5.2mm long
Back to 2 | Hibiscus richardsonii |
| 4 | Flowers either more than 5 cm long or if 3–5 cm then yellow; trees or shrubs; areas east of the Divide | 5 |
| Flowers either less than 3 cm long or if to 3.5 cm then pink; subshrubs; areas west of the Divide except for garden escapes
Back to 1 | 8 |
| 5 | Epicalyx segments free to the base; stipules linear | 6 |
| Epicalyx segments united at the base to form a cup; stipules leafy
Back to 4 | Hibiscus tiliaceus |
| 6 | Leaves with glands present on dorsal basal midrib; peduncle articulate at the base | 7 |
| Leaves without glands; peduncle articulate c. 10 mm below flower
Back to 5 | Hibiscus splendens |
| 7 | Erect or spreading shrub 1–2 m high, stems with a fine pubescence and interspersed with prickles | Hibiscus diversifolius |
| Erect shrub or small tree to 6 m or more high, glabrous or glabrescent, stems with prickles
Back to 6 | Hibiscus heterophyllus |
| 8 | Upper leaves entire; capsule silky | 9 |
| Upper leaves lobed; capsule glabrous or hairy, but not silky
Back to 4 | 10 |
| 9 | Indumentum rusty | Hibiscus sturtii |
| Indumentum white, velvety
Back to 8 | Hibiscus krichauffianus |
| 10 | Small low-growing shrub up to 0.5 m high; corolla 10–15 mm long; capsule glabrous | Hibiscus brachysiphonius |
| Shrubs 1–5 m high; corolla 30–60 mm long; capsule hairy; garden escape
Back to 8 | 11 |
| 11 | Leaf lamina of distal leaves deeply 3-lobed with central lobe obovate to narrowly obovate, longer than lateral lobes, 2–7 cm long | Hibiscus pedunculatus |
| Leaf lamina of distal leaves very broadly ovate to orbicular in outline, palmately but shallowly 3–7-lobed, 5–15 cm long
Back to 10 | Hibiscus mutabilis |
