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Ruellia tuberosa L. 1753
pronounced: roo-ELL-ee-uh too-ber-ROH-suh
(Acanthaceae – the black-eyed Susan family)
common names: Minnie Root, Fever Root, Popping Pod, Duppy Gun
Ruellia is named for Jean Ruel (1474 – 1537), French physician and botanist. He translated Dioscorides into Latin, and wrote a general botanical treatise De Natura stirpium† (1536). Tuberosa is from the Latin tuberosus, full of lumps.
A common pastime of children in many of the Pacific islands is to pick the dried pods of this plant, lick them, and throw them at other unsuspecting children. The moisture in the saliva causes the pod to pop, startling the victim and covering him with seeds and half pods, in the hair if the aim was true.
The native range of the plant is in the Caribbean region, but it has now become naturalized in many parts of tropical Asia, the Pacific Islands, and Australia. In Australia it is found in the northern parts of the Northern Territory, and in north-eastern Queensland. It generally grows in or near vine thickets.
This is a perennial with a hairy stem that grows to a height of anything up to 50 or 60 cm, but is usually around 20 cm tall. It has thick finger-like roots. The stem is 4-sided, longitudinally ridged, and hairy; the simple leaves are opposite and elliptic, with petioles 5 – 7 mm long, and blades 30 – 60 by 15 – 25 mm, and numerous cigar-shaped glands visible on both sides of the blade.
Two types of flowers are produced, normal flowers and small cleistogamous flowers. The calyx is roughly 2 cm long, the lobes linear and covered in hairs. The corolla in the normal, infundibuliform violet-coloured flowers consists of a tube about 2 – 4 cm long and 5 lobes 1 – 2 cm long, and the styles are about 2 cm long. In the cleistogamous flowers the corolla lobes are only 4 – 6 mm long.
The fruit is a cigar-shaped pod, the calyx persistent at the base, about 20 by 3 mm. It contains anything up to about 20 black seeds, and it bursts open with a bang, as mentioned above, when it gets wet, and the seeds are flung out. Each seed is about 20 by 2 mm, and clothed in hairs.
The caterpillars of some butterfly species, including the Brown Soldier (Junonia hedonia), feed on the leaves.
There are various uses for the plant in traditional medicines. An infusion of the leaves is used as a diuretic, a laxative, and for treating liver diseases. It is also said to reduce inflammation, temperature, pain, asthma, male impotence and diabetes. The roots are used to treat stomach ache, toothache, colds, hypertension, urinary tract infections and diabetes. A herbal tea made from the flowers is also used to treat hypertension.
A dye for textiles is extracted from the plant.
† Concerning the Nature of Plants
Information about medicinal qualities of plants, or about their use as medicines, is for interest only, and is not intended to be used as a guide for the treatment of medical conditions.
Photographs taken in Picnic Bay 2010
Page last updated 3rd February 2017