Idiospermum

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.