pronounced: ur-EE-nuh low-BAH-tuh
Urena is from the Malayalam (Southern India) word uren, stinging; lobata is from the late Latin lobatus, a husk, pod.
This plant, a native of India and tropical Asia, usually flowers and fruits as an erect, woody perennial herb or a subshrub 1–2 m tall. It is single-stalked, with free-branching stems that give the plant a bushy appearance. It is now a pantropic weed; in Australia it is naturalized right across the top end, and southwards as far as north-eastern NSW. It can be found from sea level up to an altitude of about 1,000 m, and usually grows along roads in rainforest and monsoon forest, and also in disturbed areas.
The leaf blades are broadly ovate to more-or-less orbicular, shallowly lobed, about 2 –7 by 2 – 8 cm. Both upper and lower surfaces of the leaf blades, petioles and twigs are covered in stellate hairs. The stipules are linear, 2 – 4 mm long. One or more glands are present on the midrib and major veins near the base and on the underside of the leaf blade. The twig bark is strong and fibrous when stripped.
The flowers are small, showy, hibiscus-like, solitary on short stalks in the leaf axils; the pedicels are 1 – 5 mm long; the epicalyx about 7 – 8 by 5 – 6 mm, larger than the calyx proper; the outer surface of the calyx is clothed in stellate hairs. There are 5 petals, rose or pink, darker at the base, rounded, to 1.5 cm long; the stamens are fused into an obvious pink column beneath a 5-lobed style. The pollen grains are very large, easily seen with a hand lens. There are 8 stigmas, dark purple and hairy.
The fruit capsules are globose or depressed globose, about 1 cm in diameter, clothed in numerous spines each ending in about 4 – 6 minute hooks, so that the end of each spine resembles a miniature grappling iron. These hooks cause the fruits to adhere to clothes, horses’ manes and tails, and other similar objects, and so spread the seeds.
The whole plant is used in Indian Ayurvedic medicine to treat colic, coughs, bronchitis, asthma, low back pain, arthritis, tuberculosis and general weakness.
In Vietnam it is an important local medicine. Fever is treated by drinking a decoction of the roots; rheumatism is treated by boiling fresh roots with a pig’s trotter in a mixture of water and alcohol for 3 hours, then drinking the liquid and eating the trotter; for enteritis and dysentery a decoction of the whole plant is used, or, alternately, the roots may be chewed; for tuberculosis and its associated coughing, fresh and tender leaves of the plant are cooked in a pot with an adequate amount of pork, and the liquid drunk; for snakebite and asthma fresh leaves are boiled up with rice, and the paste from this applied to the bite, or the liquid drunk.
The caterpillars of the Transverse Moth Xanthodes transversa feed on the plant.
In some parts of Africa, the leaves and flowers are eaten as a famine food.
