Crotalaria spectabilis
(showy rattlepod)

Preferred Scientific Name

• Crotalaria spectabilis Roth.

Preferred Common Name

• showy rattlepod

Other Scientific Names

• Crotalaria altipes Raf.
• Crotalaria cuneifolia (Forssk.) Schrank
• Crotalaria leschenaultii DC.
• Crotalaria macrophylla Wienmann
• Crotalaria retzii Hitchc.
• Crotalaria sericea RETZ.
• Crotalaria spectabilis subsp. spectabilis

International Common Names

• English: cat's bell; rattlebox; rattlepod; showy crotalaria; showy rattlebox; silent rattlepod
• French: crotalaire remarquable
• Chinese: da tuo ye zhu shi dou

Local Common Names

• Cuba: chicharra ; maromera; maruga
• Dominican Republic: maraquita
• Germany: Ansehliche Klapperhuelse
• India: dhundhunia; jhunjhunia; rattle box; sani; showy crotalaria; sonnette; tcha-tcha
• Thailand: mahing men
• USA: showy rattlebox

EPPO code

• CVTSP (Crotalaria spectabilis)

• Domain: Eukaryota
•     Kingdom: Plantae
•         Phylum: Spermatophyta
•             Subphylum: Angiospermae
•                 Class: Dicotyledonae
•                     Order: Fabales
•                         Family: Fabaceae
•                             Subfamily: Faboideae
•                                 Genus: Crotalaria
•                                     Species: Crotalaria spectabilis

Fabaceae is one of the most diverse families of flowering plants. Species in the subfamiliy Papilionoideae (also known as Faboideae) are trees, shrubs, and herbs that may be easily recognized by their classical pea-shaped flowers and the frequent occurrence of root nodulation (Stevens, 2012).

The genus Crotalaria includes around 720 species especially distributed in the Southern Hemisphere throughout tropical regions and extending into the subtropics (Roux et al., 2013; Flora of China Editorial Committee, 2015). The name Crotalaria derives from the Greek krotalos for rattle, refering to the sound dried pods make when shaken: the common name for the genus, rattlebox or rattlepod, also refers to the rattling of seeds in the pods after drying.

 A recent molecular systematic study based on nuclear internal transcribed spacer and the plastid markers matK, psbA-trnH and rbcLa showed that Crotalaria is monophyletic (Roux et al., 2013). Crotalaria species are easily recognized by the following combination of characters (Wyk, 2005):

• rostrate keel

• highly inflated fruit

• hairy style

• 5 + 5 anther configuration

• paired callosities on the standard petal

• presence of macrocyclic pyrrolizidine alkaloids

C. spectabilis is an erect herb 0.6-1.5 m tall. Branches terete, glabrous. Stipules ovate-triangular, approximately 1 cm. Leaves simple; petiole 2-8 mm; leaf blade oblanceolate to narrowly elliptic, 7-15 × 2-5 cm, thin, abaxially appressed silky pubescent, adaxially glabrous, base broadly cuneate, apex obtuse and mucronate. Racemes terminal, 20-30-flowered; bracts ovate-triangular, 7-10 mm. Pedicel 1-1.5 cm; bracteoles inserted at or apical to middle of pedicel, linear, approximately 1 mm. Calyx 2-lipped, 1.2-1.5 cm, glabrous; lobes broadly lanceolate-triangular, longer than tube. Corolla pale yellow; standard veined purplish red, suborbicular to oblong, 1-2 cm, base with 2 appendages, apex obtuse to retuse; wings obovate, approximately 2 cm; keel rounded about middle, with a fairly short and slightly incurved twisted beak beyond calyx. Legume broadly oblong, 2.5-3 × 1.5-2 cm, 20-30-seeded, shortly stipitate, glabrous. Seeds smooth, dark brown, 4.5 mm long (Flora of China Editorial Committee, 2015).

C. spectabilis has been widely introduced throughout the tropics to be used as fodder, green manure, for soil conservation, and as a soil improver and ornamental. However, the use of this species has been abandoned because of the toxic alkaloids that it contains (Francis, 2004). In the United States, it was introduced from the Indo-Malaysian area (Maddox et al., 2011). In the West Indies, C. spectabilis appears in herbarium collections made in 1937 in Dominica, in 1939 in Martinique, and in Cuba in 1950 (US National Herbarium).

Soil drainage

• free

Soil reaction

• acid
• alkaline
• neutral

Soil texture

• heavy
• light
• medium

Special soil tolerances

• saline
• shallow

C. spectabilis spreads by seeds. Seeds are primarily dispersed as a contaminant of soil, agricultural equipment, crop seeds and hay (Maddox et al., 2011). The species is intentionally planted in cultivated lands where is used as a green manure and for erosion control (Niyomdham, 1997).

Like other Crotalaria species, C. spectabilis contains pyrrolizidine alkaloids, which are present in greatest quantity in the seeds. Therefore, C. spectabilis can be poisonous to all livestock including poultry (chickens, turkeys and quail), horses, goats and dogs, particularly when seeds are consumed (Francis, 2004; Maddox et al., 2011). This species is also a weed negatively impacting maize and soyabean plantations and pastures (Niyomdham, 1997; Francis, 2004; Maddox et al., 2011).

C. spectabilis has escaped from cultivation and naturalized in disturbed areas, roadsides, waste ground, grasslands, disturbed forests, and mangrove edges (Liogier, 1988; Wagner et al., 1999; Francis, 2004; Maddox et al., 2011). Once naturalized,this species grows as a weed and may become invasive, displacing native vegetation (ILDIS, 2015; USDA-NRCS, 2015). As with many other Crotalaria species, C. spectabilis is a nitrogen-fixing species and consequently it has the capacity to alter chemical soil conditions, nutrient cycling and trophic levels in invaded ecosystems, with negative effects on native vegetation principally in nutrient-poor ecosystems that did not previously contain nitrogen-fixing residents (Levine et al., 2003).

• Proved invasive outside its native range
• Has a broad native range
• Abundant in its native range
• Highly adaptable to different environments
• Is a habitat generalist
• Tolerates, or benefits from, cultivation, browsing pressure, mutilation, fire etc
• Pioneering in disturbed areas
• Highly mobile locally
• Benefits from human association (i.e. it is a human commensal)
• Fast growing
• Has high reproductive potential
• Gregarious

• Altered trophic level
• Damaged ecosystem services
• Ecosystem change/ habitat alteration
• Loss of medicinal resources
• Modification of nutrient regime
• Modification of successional patterns
• Monoculture formation
• Negatively impacts agriculture
• Negatively impacts animal health
• Reduced native biodiversity
• Threat to/ loss of native species

• Competition - monopolizing resources
• Competition - smothering
• Poisoning
• Rapid growth

• Highly likely to be transported internationally accidentally
• Highly likely to be transported internationally deliberately
• Difficult to identify/detect as a commodity contaminant
• Difficult to identify/detect in the field

C. spectabilis is used as a green manure, for erosion control and for soil improvement in the tropics and in the USA. It serves as a nurse species during early reforestation. Its use as forage and fodder has ceased because of its toxicity. It is also planted as an ornamental (Niyomdham, 1997). This species is also used in Asian traditional medicine. Extracts of the whole plant are used to treat impetigo and scabies, as an antiseptic for cuts, and to treat intestinal worms (Parrotta 2001; Francis, 2004).