Australian Tropical Rainforest Plants - Online edition

Idiospermum australiense (Diels) S.T.Blake

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Leaves and Flowers. © CSIRO
Leaves and Flowers. © CSIRO
Fruit, side view and two seeds. © W. T. Cooper
Scale bar 10mm. © CSIRO
10th leaf stage. © CSIRO
Cotyledon stage, hypogeal germination. © CSIRO

Blake, S.T. (1972) Contributions from the Queensland Herbarium 12: 5.

Common name

Idiot Fruit; Ribbonwood; Idiospermum


Blaze darkening on exposure. Living bark very bitter when chewed and probably quite poisonous.


Leaf blades about 10-17 x 3.5-5.5 cm. Lateral veins slightly raised on the upper surface, curved throughout their length, but not forming definite loops.


Tepals about 12-14 mm long, numerous, about 30-40, variable, changing from bracts to sepals-petals-stamens-staminodes-carpels as the centre of the flower is approached. Anther connective extending beyond the anthers, both laterally and apically.


Fruits large, depressed globular, about 5-5.5 x 6-6.5 cm. Seeds large, about 4-5 x 5-6 cm. Cotyledons three or four, large, thick and fleshy.


Cotyledons three or four, greenish brown, remaining at ground level until well after the tenth leaf stage. At the tenth leaf stage: leaf blade oblong to ovate, apex acuminate, base obtuse, glabrous; petiole glabrous. Seed germination time 31 to 74 days.

Distribution and Ecology

Endemic to NEQ, occurs in the area between Hutchinson Creek and the Daintree River and the foothills of the Bellenden Ker Range and Mt Bartle Frere. Altitudinal range from near sea level to 200 m. Grows in well developed lowland rain forest.

Natural History & Notes

Based on field evidence the fruits of this species is poisonous to cattle. Everist (1974). Other parts of this species are also likely to be poisonous.

Calycanthus australiensis Diels, Bot. Jahrb. 48: 10(1912), Type: Qld, Russel River, Harvey Creek, 6 June 1902, Diels 8548. Holo: B destroyed. Neo: Harvey Creek, 19 Jul. 1998, S. Worboys SJW346. Holo: BRI.
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