pronounced: kroh-tuh-LAH-ree-uh MON-tah-nuh
Crotalaria comes from the Greek κροταλον (krotalon), a rattle or castanets, referring to the sound the dried seed pods make when shaken; montana is from the Latin montanus, belonging to a mountain.
This is an erect bushy plant that grows to about 1 m tall. It is widespread in tropical America, and perhaps also indigenous in Africa and Madagascar. It is now found in most other parts of the tropics. It is established in most tropical and subtropical parts of Australia, and is fairly common along roadsides and pathways on Magnetic Island.
The stems are whitish at first, then rust-coloured, and have short yellowish hairs. The leaves have 3 leaflets, each about 4 cm long, broadest above the middle.
The many-flowered racemes are up to 30 cm long, the pedicels 3 – 5 mm. The calyx is about 8 mm long, and pubescent. The corolla scarcely exceeds the length of the calyx. It is pale yellow, with reddish veins, and the wings are slightly shorter than the keel, which has a narrow beak 4 – 6 mm long, twisted at the apex.
The pod is usually 2.5 – 3.5 cm long, tan, dark brown or dark grey to blackish at maturity, and glabrous. The seeds, about 40 per pod, are tiny, only about 2 mm long, dark brown to greenish, and shiny.
In Paraguay, the flowers and unripe fruits are used as an abortifacient, and the rattling pods are thought to be a magic cure for mute or stuttering children (‘because the plant speaks’). In other places a tea made from the roots is used in folk medicine to treat yellow fever and rashes.
The plant fixes atmospheric nitrogen in a form usable by other plants, and so this rattlepod can be a valuable soil-conditioning green manure.
The various Crotalaria species are food plants for several caterpillars, including those of:
• the Pea Blue Lampides boeticus;
• the Crotalaria Podborer Argina astraea; and
• the Crotalaria Moth Utetheisa lotrix.
The entire plant contains several alkaloids, including the highly toxic retrosine, which can damage the liver and the lungs. A similar species popularly used as a bush tea in Jamaica has been found to block some of the small veins in the liver of animals, and it is thought that the passage of the toxin to infants in their mothers’ milk may be the cause of similar effects in the livers of children whose mothers drink the bush tea. The consumption of the plant has caused the death of grazing animals.
