Australian Tropical Rainforest Plants - Online edition

Polyalthia johnsonii (F.Muell.) B.Xue & R.M.K.Saunders

Shrub (woody or herbaceous, 1-6 m tall)
Click/tap on images to enlarge
Flower. © CSIRO
Leaves and fruit. © Barry Jago
Scale bar 10mm. © CSIRO
Cotyledon stage, semi-hypogeal germination. © CSIRO
10th leaf stage. © CSIRO

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


Shrub to 4 m tall.


Oak grain in the twigs. Leaf blades about 4-9 x 1-3 cm. Petiole very short (about 0.2-0.3 cm long). Lateral veins forming loops inside the blade margin. Oil dots visible with a lens. Twig bark strong and fibrous when stripped. Young twigs and terminal buds hairy.


Flowers small, about 6-10 mm diam. Sepals about 1.5 x 1.5 mm. Outer petals triangular, about 4-5 x 3.5 mm, wide spreading. Inner petals about 5 x 2-2.5 mm, joined at the apex to form an arch over the stamens and ovaries. Stamens about 30. Ovaries about six. Ovules 2 per ovary. Stigmas globose, sessile on the ovaries.


Fruiting carpels +/- globular, about 12-17 x 9-13 mm, on a stalk about 2-3 mm long, surface glabrous or closely appressed puberulent. Seeds about 4-7 x 4 mm, usually two per carpel. Embryo minute.


First pair of leaves shortly petiolate, alternate, ovate, margins smooth, sparsely pubescent. Small oil dots visible with a lens. Stem clothed in yellowish or pale brown hairs. At the tenth leaf stage: stem somewhat zig-zagged. Leaves elliptic to ovate, apex obtuse, base cordate to oblique. Leaf blades about 70-75 x 30 mm, petioles somewhat swollen, about 3.5 mm long. Oil dots numerous, very small, visible with a lens. Lateral veins form a double series of loops inside the blade margin. Seed germination time 92 to 172 days.

Distribution and Ecology

Endemic to NEQ, the collections to date indicate that it is restricted to the foothills of Mt Bartle Frere, the base of the Bellenden Ker Range. Altitudinal range from near sea level to 700 m. Usually grows in lowland rain forest.

Natural History & Notes

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

Haplostichanthus johnsonii F.Muell.The Victorian Naturalist 7: 180 (1890). Type: Mount Bartle-Frere; Stephen Johnson. Monostichanthus johnsonii F.Muell., Descriptions of new Australian Plants, with occasional other annotations : ? (1891).
RFK Code
Copyright © CSIRO 2020, all rights reserved.