Leaves often lobed, margins usually crenate or toothed.
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.
Capsule loculicidally 5-valved; seeds glabrous, tomentose or woolly.
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||Hibiscus trionum|
|Trees, shrubs or subshrubs; calyx neither membranous nor inflated after flowering||2|
|2||Flowers either more than 5 cm long or if 3–5 cm then yellow; trees or shrubs; areas east of the Divide||3|
|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|
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|3||Epicalyx segments free to the base; stipules linear||4|
|Epicalyx segments united at the base to form a cup; stipules leafy|
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|4||Leaves with glands present on dorsal basal midrib; peduncle articulate at the base||5|
|Leaves without glands; peduncle articulate c. 10 mm below flower|
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|5||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|
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|6||Upper leaves entire; capsule silky||7|
|Upper leaves lobed; capsule glabrous or hairy, but not silky|
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|7||Indumentum rusty||Hibiscus sturtii|
|Indumentum white, velvety|
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|Hibiscus krichauffianus |
|8||Small low-growing shrub up to 0.5 m high; corolla 10–15 mm long; capsule glabrous||Hibiscus brachysiphonius|
|Shrub 1–3 m high; corolla 30–40 mm long; capsule hairy; garden escape|
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