Idiospermum australiense

Idiospermum is a monotypic genus (that is, a genus that contains only one species) in the family Calycanthaceae. The sole included species is Idiospermum australiense − commonly known as ribbonwood, dinosaur tree, or the misnomer idiotfruit − which is found only in two small areas of the tropical rainforests of northeastern Queensland, Australia. It has the largest seed embryo of any flowering plant, and is the only flowering plant with more than two cotyledons. It is a relic of the ancient forests of Gondwana, surviving in very localised refugia for 120 million years, and displaying features (of the flowers in particular) that are almost identical to fossil records from that time. As such it provides an important insight into the very early evolution of flowering plants.

==Description== Idiospermum australiense has, in contrast to its weighty evolutionary significance and its extraordinarily unique fruit, a rather nondescript overall appearance. It is a broadleaf evergreen tree growing to around tall, with a maximum trunk diameter of around . The leaves are simple (without lobes or divisions), opposite and glabrous (without hairs). They measure up to long by wide, with 7−10 pairs of lateral veins. They are held on petioles measuring long, and the leaf blades exhibit numerous 'oil dots' or pellucid glands (tiny, translucent spots) when held up against a strong light source.