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(Last Modified On 9/25/2013)
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(Last Modified On 9/25/2013)
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Genus
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CROTALARIA L.
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Contributor
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Donald R. Windler and Leo McLaughlin
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PlaceOfPublication
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Sp. P1. 714. 1753
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Note
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TYPE: C. lotifolia L. (see Polhill, 1968).
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Description
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Herbs or shrubs, erect to prostrate. Leaves ternately compound or unifoliolate by reduction; leaflets entire, glabrous or pubescent, subtended by stipules; stip-
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Habit
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Herbs or shrubs
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Description
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ules varying greatly in size and shape. Inflorescences racemes, peduncles ter- minal or opposite leaves, bracts setaceous to foliaceous; bracteoles paired, similar in shape to the bracts and located on the pedicel or the calyx. Flowers sometimes showy, bisexual, 5-merous; calyx green, the bilabiate tube usually campanulate, glabrous or pubescent, the lobes usually longer to much longer than the tube; corolla papilionaceous, usually yellow (blue in C. verrucosa), standards orbicular or obovate, the apex rounded or retuse, the base clawed, the adaxial surface and veins near the base frequently becoming red-tinged, the wing petals oblong, at- tached to a stalk continuous with the lower margin (cleaver-shaped), the blades usually puckered between some of the veins, the keel petals usually twisted at the tip, lanate ciliate; stamens 10, monadelphous, the staminal tube open on the upper side, the anthers dimorphic with basifixed long anthers alternating with medifixed short anthers, the short anthers positioned above the elongate at an- thesis; ovary terminated by a geniculate style. Fruit an inflated, sub-cylindric, sessile or short stipitate legume, glabrous or pubescent, the fruits of some species becoming black at maturity; seeds 7-46 per legume, oblique cordiform, the testa smooth and usually impervious to water.
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Note
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Crotalaria is a genus of about 550 species, over 400 of which occur in Africa and about 70 of which appear to grow naturally in the New World. Polhill (1968) published a reorganization of sections in the genus based on floral morphology. Panamanian plants fall into five of Polhill's sections: Calycinae-C. pilosa, C. rotundifolia, C. sagittalis; Crotalaria-C. longirostrata, C. retusa, C. spectabilis, C. verrucosa; Incanae-C. incana; Stipulosae-C. cajanifolia, C. maypurensis, and C. micans. Some species of Crotalaria have been used as cover crops and green manure crops in tropical countries. Crotalaria juncea, the sunnhemp of India, used for its fiber content, is probably the most economically important member of the genus. Monocrotaline, an alkaloid isolated from C. spectabilis has been shown to be active as a cancer retardant. A few species have been used as ornamentals and the young shoots and leaves of a few species have been used as pot herbs. Ingestion of mature Crotalaria tissue has been shown to be toxic due to the alkaloids which it contains. These alkaloids cause such symptoms as lesions in the heart, liver and kidneys, mast cells in the lungs, pulmonary hypertension, and heart failure. Although no specimens of Crotalaria pumila Ortega have been observed from Panama, this weedy species should be expected. Collections of C. pumila are known from the United States, Mexico, Guatemala, Belize, Honduras, Nicara- gua, Venezuela, Ecuador, Peru, Brazil, Bolivia, and Argentina. The species is a variable low growing, less than 0.6 m tall, trifoliolate herb which has small flow- ers, usually less than 10 mm long, with an elongated keel. It most closely resem- bles the larger, woody C. Iongirostrata. The two species can usually be separated on the basis of plant size: C. pumila 0.05-0.60 m tall, C. longirostrata-0.7-3.0 m tall.
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Reference
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Polhill, R. 1968. Miscellaneous notes on African species of Crotalaria L., II. Kew Bull. 22: 169-348. Senn, H. A. 1939. The North American species of Crotalaria. Rhodora 41: 317- 367. Windler, D. R. 1974. A systematic treatment of the native unifoliolate Crotalarias of North America. Rhodora 76: 151-204.
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Key
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a. Leaves unifoliolate. b. Leaves broadly rhombic or ovate; stipules crescent shaped; stems ridged; flowers blue or white and violet ...... 11. C. verrucosa bb. Leaves not rhombic or ovate; stipules other than crescent shaped; stems terete; flowers yellow. c. Leaves oblanceolate; bracteoles attached to the pedicel; calyx glabrous or strigulose; fruits brown at maturity. d. Stipules and bracts persistent, ovate, 0.5-1.5 cm long; calyx glabrous ...... 10. C. spectabilis dd. Stipules and bracts caducous, narrow, 0.2-0.3 cm long; calyx strigulose ...... 7. C. retusa cc. Leaves elliptic, lanceolate, or narrowly lanceolate; bracteoles attached to the calyx; calyx not glabrous; fruits black at maturity. e. Stipules decurrent for more than one internode; inflorescence terminal ...... 6. C. pilosa ee. Stipules decurrent for less than one internode; inflorescences leaf opposed. f. Plants erect ...... 9. C. sagittalis ff. Plant decumbent or prostrate ...... 8. C. rotundifolia aa. Leaves trifoliolate. g. Inflorescences leaf opposed; stems usually terete ...... 1. C. cajanifolia gg. Inflorescences terminal or appearing so; stems usually striate. h. Petiole equal to or longer than the terminal leaflet; calyx lobes more than twice as long as the tube; bracteole at the junction of the pedicel and the calyx; fruits villous, trichomes often to 2.0 mm long ...... 2. C. incana hh. Petiole shorter than the terminal leaflet; calyx lobes less than twice as long as the tube; bracteole attached to the pedicel; fruits strigulose, trichomes usually less than 0.5 mm long. i. Calyx lobes nearly twice as long as the tube; standard 1.4-1.9 cm long (measured from the base of the calyx to the apex of the standard in the closed flower); keel not prolonged, bearing a cluster of trichomes on the external surface; fruit usually longer than 3 cm. j. Inflorescences crowded, usually with a tuft of curved bracts at the apex ...... 5. C. micans jj. Inflorescences lax, lacking a tuft of curved bracts at apex ...... 4. C. maypurensis ii. Calyx lobes about the same length as the tube; standard 1.3 cm or less; keel long attenuate no trichomes present on the external surface of the keel; fruit less than 3 cm long ...... 3. C. longirostrata
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