Australian Tropical Rainforest Plants - Online edition

Hibiscus macilwraithensis (Fryxell) Craven & B.E.Pfeil

Shrub (woody or herbaceous, 1-6 m tall)
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Flowers. © B. Gray
Flowers. © CSIRO
Scale bar 10mm. © CSIRO
10th leaf stage. © CSIRO
Cotyledon stage, epigeal germination. © CSIRO

Craven, L.A. & Pfeil, B.E. (2004) Adansonia 26(2): 237.


Usually flowers and fruits as a shrub about 1-4 m tall.


Both the upper and lower surfaces of the leaf blade, petioles and twigs clothed in stellate hairs, sometimes sparsely. Leaf blades have a rough texture but not abrasive enough to be classed as sandpapery. Stipules linear, filiform, about 0.4-1 cm long. Leaf blades about 12.5-17 x 4-5 cm. Lateral veins looping inside the blade margin. Twig bark clothed in stellate hairs, strong and fibrous when stripped.


Pedicel about 10-50 mm long. Epicalyx segments about six or seven, free or almost completely free to the base. Calyx about 10-15 mm long, fused to form a tube, outer surface densely clothed in stellate hairs and scales. Petals mainly cream, about 18-22 mm long. Stamens about 20, anthers horseshoe-shaped with a line of dehiscence on the outer periphery. Filaments attached to the middle of the anther.


Capsules subglobose, about 10-15 x 12-14 mm, outer surface clothed in stellate hairs. Calyx and epicalyx persistent at the base of the fruit. Seeds about 5 x 3 mm, clothed in white simple hairs. Cotyledons folded or rolled, about 4.5 x 2.5 mm, radicle straight, about 2.5 mm long.


Cotyledons about 12-19 x 12-17 mm, +/- reniform, apex notched, base auriculate to cordate, petioles about 2-4 mm long, clothed in short white hairs. First pair of leaves obovate, margin obscurely toothed at least towards the apex. Stellate hairs usually visible on one or both of the leaf surfaces. Stipules about 2 mm long. At the tenth leaf stage: leaf blade obovate, about 11 x 3.5 cm, apex acute, base obtuse to truncate, stem and both the upper and lower surfaces of the leaf blade sparsely clothed in pale stellate and simple hairs. Petioles about 4 mm long. Midrib raised on the upper surface of the leaf blade. Margin +/- undulate. Stipules terete, about 3-4 mm long, sparsely clothed in stellate hairs. Seed germination time 27 to 37 days.

Distribution and Ecology

Endemic to CYP. Altitudinal range from near sea level to 400 m. Grows in or on the margins of various types of rain forest and monsoon forest.

Natural History & Notes

This small to medium shrub has potential for tropical gardens producing interesting white flowers.

Macrostelia grandifolia subsp. macilwraithensis Fryxell, Australian Journal of Botany 22: 191(1974), Type: Queensland, McIlwraith Range, c. 11 miles NE. by E. of Coen, 12 Oct. 1962, L. S. Smith 11783; holo: BRI.
RFK Code
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