Common Name: Smooth Rattlebox

General Information

Crotalaria pallida is an erect, well-branched, sometimes robust perennial herb with stems that become more or less woody. It can grow up to 2 metres tall[, , ].
The plant has a fairly long history of cultivation as a green manure and ground cover crop, though it is much less grown at present due to its susceptibility to pests and diseases in Asia[]. It is still often cultivated in southeastern USA[].

Known Hazards

Seeds of many Crotalaria spp., including this species, contain a number of pyrrolizidine alkaloids, such as mucronatine and monocrotaline which affect the liver and may kill birds and mammals[]. They are particularly insidious toxins, as their effects may only become apparent weeks or months after the animal has stopped eating the seeds[].
The concentrations are low in this species and toxic effects have only been observed when chicks were fed the seeds for several weeks[].
The leaves contain an alkaloid poisonous to goats; the dried leaves are not toxic[].
Pyrrolizidine alkaloids have a cumulative effect upon the body and, unless concentrations in a plant are high, occasional use is generally completely safe. They are derived from amino acids including ornithine. Many pyrrolizidine alkaloids have pronounced hepatic toxicity, but the lungs and other organs may be affected as well. Mutagenic and carcinogenic activities of pyrrolizidine alkaloids have also been reported[].

Botanical References

, ,

Range

Tropical Africa, though it is naturalised in many parts of the tropics.

Habitat

Occurs naturally on river banks, edges of lakes, extending into woodland, grassland and waste places from sea level to elevations of 1,000 metres[]. Grassland and sandy areas in southern China[].

Properties

Weed Potential	Yes
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Perennial
Height	2.00 m
Cultivation Status	Cultivated, Wild

Cultivation Details

A plant of the lowland tropics and subtropics, where it has been successfully grown at elevations up to 1,800 metres[]. It grows in a wide range of annual rainfall conditions, from 850 mm to over 3,000 mm, and occurs occasionally in rather dry locations[]. The average annual temperature varies from 16 - 26°c[].
Succeeds on a wide range of soils, except on peat soils that developed under coarse grass[]. It is considered well suited to sandy soils[] and has succeeded in saline conditions in Thailand[]. It requires a sunny position, growing poorly in shade[].
Often grown as a green manure, the plant can escape from cultivation and become naturalized. It is reported to be invasive in many areas, where it grows in open and disturbed sites such as pastures, waste ground, roadsides and sand dunes at elevations up to 1,070 metres[].
This species has a symbiotic relationship with certain soil bacteria, these bacteria form nodules on the roots and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby[, ].

Edible Uses

A fermented product known as 'dage' is made from the seeds[]. The seeds are boiled for two hours, then wrapped in banana leaves and left to ferment for several days in order to remove poisonous components[].

The flowers are used as a vegetable[].

A kind of coffee is prepared from roasted seed[, ]. Washing then roasting the seeds removes any toxic alkaloids[].

The roots are sometimes chewed with betel-nut[].

Medicinal

The plant is used in traditional medicine to treat urinary problems[]. The plant is also used to reduce fever[].
An infusion of the plant is used to bathe children in order to prevent skin infections and also to treat thrush[]. Boiled with salt, it is used to treat eczema and other skin problems[].

A poultice made of the roots is applied to painful swelling of joints[].

An extract of the leaves is taken as a vermifuge[].
The leaves are used to treat wounds[].

A lectin from Crotalaria pallida, which specifically agglutinates type A erythrocytes, is used in cytochemical research[].
The flavonoids apigenin and vitexin have been isolated from the bark and the leaves[].
Alkaloids from the seed have shown antitumor activity[].

Agroforestry Uses:

The plant is used as a ground cover and a green manure crop throughout the humid tropics, though on a limited scale[]. In tea, rubber and coconut plantations in Sri Lanka and South-East Asia, and in cocoa plantations in West Africa, it is used as a green manure and planted in the inter-rows to reduce erosion[]. It is one of the oldest green manure crops in Indonesia, but lost popularity because of its susceptibility to diseases and pests[].

Other Uses

None known

Propagation

Seed - pre-soaking the seed for 12 hours in warm water can help to reduce germination time. If you have sufficient seed then it can be sown in situ. Otherwise sow in trays in a nursey and, when the seedlings are large enough to handle, pot them up into individual pots. Plant out when 15cm or more tall.

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