Australian Tropical Rainforest Plants - Online edition

Polyalthia fruticosa (Jessup) B.Xue & R.M.K.Saunders

Shrub (woody or herbaceous, 1-6 m tall)
Click/tap on images to enlarge
Flowers. © CSIRO
Fruit, side view, seed. © W. T. Cooper
Scale bar 10mm. © CSIRO
Cotyledon stage, durian germination. © CSIRO
10th leaf stage. © CSIRO

Xue, B., Su, Y.C.F., Thomas, D.C. & Saunders, R.M.K. (2012) Taxon 61(5): 1034.


Usually flowers and fruits as a shrub about 1-3 m tall.


Leaf blades about 6-13.5 x 2.2-3.5 cm, petioles 0.2-0.7 cm long. Lateral veins often form a double series of loops inside the blade margin. Young shoots clothed in brown hairs. Fine oak grain visible in the twigs.


Flowers about 10-11 mm diam. Sepals and petals hairy on the outer surface. Sepals about 3 x 2 mm. Outer petals triangular, about 7 x 6 mm. Inner petals oblong, about 6-7 x 4 mm, fused, forming an arch over the ovaries and stamens. Ovaries 2-10. Ovules 1 or 2 per ovary.


Fruiting carpels about 7-11 x 7-9 mm. Usually 2-10 carpels developed in each fruit with one or sometimes two seeds per carpel. Seeds about 6-8 x 6-7 mm. Endosperm ruminate, the ruminations deep and regular. Embryo very small, less than 1 mm long. Embryo at the base of the seed.


First pair of leaves glabrous on the upper surface but sparsely clothed in short hairs on the lower surface. Oil dots visible with a lens. Lateral veins forming loops inside the blade margin. Stem and hypocotyl clothed in short pale brown hairs. At the tenth leaf stage: leaf blade elliptic, apex obtuse to retuse, base cordate. Lateral veins about 7, forming loops inside the blade margin. Midrib depressed on the upper surface of the leaf blade. Small oil dots visible with a lens at least from below. Stem clothed in short brownish hairs. Seed germination time 223 to 242 days.

Distribution and Ecology

Endemic to CYP, known from Moa Island, Bamaga, Olive River, Iron Range and McIlwraith Range areas. Altitudinal range from near sea level to 500 m. Grows as an understory plant in gallery rain forest, beach forest and upland rain forest.

Natural History & Notes

Food plant for the larval stages of the Green Spotted Triangle Butterfly. Sankowsky & Neilsen (2000).


Haplostichanthus fruticosus Jessup, Flora of Australia 2: 449 (2007). Type: Queensland, Williams Springs, 22.4 km NE of Bamaga, 17 Feb. 1994, D.G. Fell DGF3784 J.P. Stanton & C. Roberts. Holo: BRI.  Haplostichanthus sp. Rocky River Scrub (P.I.Forster 10617), Names Distr. Qld Plants, Algae & Lichens : 16(2002). Haplostichanthus sp. Rocky River Scrub (P.I. Forster PIF10617), Australian Tropical Rain Forest Plants, Trees, Shrubs & Vines : (2003).

RFK Code
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