Australian Tropical Rainforest Plants - Online edition

Trigonostemon inopinatus Airy Shaw

Shrub (woody or herbaceous, 1-6 m tall)
Click/tap on images to enlarge
Flower [not vouchered]. © G. Sankowsky
Leaves and flower [not vouchered]. © G. Sankowsky
Leaves and flowers [not vouchered]. © G. Sankowsky
Fruit [not vouchered]. © G. Sankowsky
Herbarium sheet. CC-BY: BRI.
Herbarium sheet: flower. CC-BY: BRI.
Herbarium sheet: fruit. CC-BY: BRI.

Airy Shaw, H.K. (1976), New or noteworthy Euphorbiaceae. Kew Bulletin 31(2):396. Type: QUEENSLAND. S. Kennedy District: Cawley State Forest, W. of Cathu, between Mackay and Proserpine, mixed notophyll vine forest (Webb, 1966) on soils derived from granite, rainfall approx. 70" (175 cm), alt. 600 m, June 1965, Webb & Tracey 7762 (type, BRI)"


Shrub or small tree 3-6 m tall. Young parts densely hairy soon becoming more or less hairless (glabrescent).


Leaves simple, alternate, sparsely hairy with appressed hairs on both surfaces. Stipules absent(none seen). Petiole to 2.5 cm long; 2-5 conical glands often found at junction of leaf blade and petiole. Leaf blade elliptic, rarely obovate, about 4-12 cm long, 2-5 cm wide, base cuneate to narrowly rounded, margins entire or with very shallow rounded teeth and undulate margins (sinuate-crenate), apex acuminate to acute. Midrib slightly raised above. Lateral veins with curving loops inside the blade margin.


Inflorescences paniculate, axillary . Both male and female flowers produced on the same plant and inflorescence (although perhaps not always present at the same time). Female flowers appearing terminal on inflorescence, male flowers borne on axes arising below female flower. Peduncle 8-27 mm long, foliar bracts lanceolate to oblanceolate 10 mm long, 3 mm wide, covered with appressed hairs. Male flower: pedicel up to 10 mm long, with indumentum of appressed hairs. Sepals 5, free, lanceolate, 3-5 mm long, appressed hairy on inner and outer surface. Petals 5, free, obovate to broadly obovate, glabrous, cream yellow or cream with reddish base or blackish red. Disk of 5 glands at base of staminal column, column stout about 2 mm long; anthers 3, c. 1.5 mm long, dorsifixed, connective between pollen sacs prominently grooved. Female flowers: pedicel up to 10 mm long, with indumentum of appressed hairs. Sepals 4-5, free, lanceolate or narrowly elliptic, 6-12 mm long, 1.5-4 mm wide, appressed hairy on inner and outer surface. Petals 5, free, 5-6 mm long, glabrous, cream yellow and red at base. Ovary more or less pyriform (pear-shaped), with few appressed hairs at base.


Pedicels 17-25 mm long. Capsules globular, about 13 mm diam., trilocular, green. Sepals persistent at the base of the fruit, 6-11 mm long, stigmas persistent at apex. Seeds three sided, two flat sides and dorsal side broadly convex, to 8 mm long,  8mm wide, pale tan with dark brown reticulate markings. Endosperm present, cotyledons straight and orbicular, radicle straight.


Features not available.

Distribution and Ecology

Endemic to CEQ in the region of Mt Beatrice and Eungella National Park. Altitudinal range of 80 m to 820 m. Often collected in notophyll vine forest on granite derived soils.

RFK Code
Copyright © CSIRO 2020, all rights reserved.