Crotalaria spectabilis Roth

Last updated: 06 May 2015

Scientific Name

Crotalaria spectabilis Roth


Crotalaria altipes Raf., Crotalaria cuneifolia (Forssk.) "Schrank, p.p.B", Crotalaria cuneifolia (Forssk.) Schrank, Crotalaria lechnaultii DC. [Spelling variant], Crotalaria leschenaultii DC., Crotalaria macrophylla Wienmann, Crotalaria retzii Hitchc., Crotalaria sericea Retz. [1]

Vernacular Name

English Showy rattlebox, showy crotalaria [2] [3]
Thailand Mahing men (Northern) [2]
Hawaii Kolomona [2]

Geographical Distributions

Crotalaria spec­tabilis probably originated in tropical Asia, but is now distributed pantropically. This plant is a plant of the tropics and subtropics. It occurs in open locations along forest margins and as a weed in cultivated fields, from sea level up to 1500 m alti­tude, in a wide range of soils, including heavy soils, with a pH range of 4.8-8.0. [2]

Botanical Description

C. spec­tabilis comes from the family of Leguminosae. It is an erect, much-branched annual herb, and measures up to 2 m tall. [2]

The stem and branches are angular, grooved and nearly smooth. [2]

The leaves are simple, and with persistent stipules. They are obliquely oblong-ovate, acuminate,  and measuring 3-10 mm x 2-8 mm. The petiole is 2-8 mm long. The blade is oblanceolate to obovate, and measuring (5-)8-14 cm x 3-8 cm. The upper surface is hairless while the lower surface appressed hairy. [2]

The in­florescence is 15-50 cm long which is rather lax and with many-flowered raceme. The bracts are persistent, cordate, measuring 10-20 mm x 5-10 mm, and acute or acuminate. The pedicel is 8-13 mm long. The bracteoles are 1-2 mm long and lance-shaped. The hairless sepal is bell-shaped, measures 11-14 mm long, and with 5 unequal lobes which are longer than the tube. The petal is yellow.  The wings are obovate-oblong, and measuring 9-18 mm x 5-9 mm. The keel measuring 10-14 mm x 4-9 mm is rounded about the middle, with a short, incurved and twisted beak. The 10 sta­mens are united into one group by their filaments. The anthers are dimorphic, with 5 long, basifixed anthers on a short filament that alter­nate with 5 rounded dorsifixed anthers which are on a long filament. The ovary is narrowly oblong and hairless. [2]

The fruit is a broadly clavate-oblong pod, measuring 4-5 cm x 1.5-2.5 cm, smooth, brown to dark brown when mature and with 20-24 seeds. [2]

The seed is unequal-sided heart-shaped, measuring about 3.5 mm x 4 mm, with the radicular side incurved and brown. [2]


C. spec­tabilis cultivated throughout the tropics, including Southeast Asia and in the south-eastern United States. It requires an annual rainfall of 900-2800 mm and a mean annual temperature of 12-28°C. This plant is drought-tolerant. [2]

Chemical Constituent

No documentation

Plant Part Used

No documentation

Traditional Use

No documentation

Preclinical Data

No documentation

Clinical Data

No documentation


No documentation

Poisonous Management

No documentation

Line drawing


Figure 1: The line drawing of C. spectabilis Roth


  1. The Plant List. Ver1.1. Crotalaria spectabilis Roth[homepage on the Internet]. c2013 [updated 2012 Apr 18; cited 2015 May 06]. Available from:
  2. Niyomdham C. Crotalaria spectabilis Roth In: Faridah Hanum I, Van der Maesen LJG, editors. Plant Resources of South-East Asia No. 11: Auxiliary plants. Leiden, Netherlands: Backhuys Publisher, 1997; p. 105-107.
  3. Quattrocchi U. CRC World Dictionary of Plant Names: Common Names, Scientific Names, Eponyms, Synonyms, and Etymology. Volume I A-C. Boca Raton, Florida: CRC Press LLC; 1999. p. 646.