Araujia Brot. (1818), in the family Asclepiadaceae, contains 2 or 3 species in South America. Description Climbers to 5m, sometimes woody at the base. The leaves are opposite, evergreen, softly hairy, stalked, simple, triangular. The flowers are scented, pale pink, becoming white, in small, loose umbels in the leaf axils. Sepals 5, large, joined at the base. Petals 5, fleshy, joined into a tube for around half their length, with 5 scales at the middle of the tube. Stamens 5, in the throat of the tube, the anthers attached to the stigma. The pollen is aggregated into sticky masses. Ovary superior, 2-celled, with numerous ovules per cell; style 1. Pollination is by insects, especially moths, which become trapped on the stamens by their proboscis. Fruits large, curved, and green, with soft prickles, splitting to release the seeds, which have a tuft of silky hairs at the apex.
Key Recognition Features The opposite, velvety leaves and white or pale pink flowers with large sepals; moths are often found trapped by the flowers in the morning. Evolution and Relationships The genus Araujia is related to milkweed, Asclepias L., and the starry, sky-blue-flowered Oxypetalum caeruleum (D. Don) Decne, syn. Tweedia caerulea. Don. Ecology and Geography In forests and scrub in Brazil and Peru. Comment Araujia sericifera Brot., which is commonly cultivated in warm areas and has become naturalised in parts of Australia, is called the cruel plant because it traps moths. |
