Skip to content

Plant of the month June 2018

Common Name: Ribbonwood

Scientific Name: Idiospermum australiense (Diels) S.T.Blake 

Family: Calycanthaceae




Idiospermum – from the Greek, “Idios”, unusual and “sperma”, seed.


australiense - Austalian


Endemic to the Humid Wet Tropics of NE Queensland. Between Hutchison Creek and the Daintree river, Mt Bartle Frere and the foothills of the Bellenden Ker Range.

Native Habitat

Mature lowland rainforest to 200 metres. Often in groups of 10 to 100 trees.


A medium sized, evergreen tree growing to 15 metres, with glossy leaves 10 - 17cm long and 3.5 - 5.5 cm wide.


Small and spirally arranged, (a primitive feature) with creamy white tepals that change to pink and then red as they age. They are fragrant and attract beetles and thrips as pollinators .


Fruit are large and globular, about 5 - 5.5 cm by 6 - 6.5 cm. Whilst most modern plants produce seed with one seed leaf or cotyledon (monocotyledons) or two cotyledons (dicotyledons), seedlings of the Ribbonwood have between two and five cotyledons. Seeds are black and poisonous.

Location in Garden

Australian Rainforest Garden, Palace Garden (bed 65a), Middle Garden (bed 17 and lawn 5).


Ribbonwood is one of the most primitive flowering plants on the planet and one of a large number of endemic primitive plants that make the Wet Tropics of Queensland internationally important.
This tree was first discovered in 1902 south of Cairns by a German botanist, Ludwig Diels who named it after comparing it to a fossil in the Dresden Herbarium. In the 1920’s Ribbonwood’s habitat was cleared for sugar cane farming and the tree was thought to be extinct. However in 1971 it was re-discovered in very strange circumstances. Cows belonging to a Daintree farmer died mysteriously and the government vet was called. An autopsy revealed several large seeds in the cow’s stomach, which were identified by botanist Stan Blake as belonging to Ribbonwood. The offending tree was removed by the farmer, but nearby Blake found another stand of trees and seedlings. The fruit is large and heavy and the seeds are so poisonous, no animals or birds eat them. This helps to explain the tree’s limited distribution. Seeds may once have been dispersed by Australia’s ancient megafauna, most of which went extinct in the Pleistocene era (1.6 million to 10 000 yrs ago).

Download June's Plant of the Month