Chamaecrista diphylla (L.) Greene

  • Authors

    Howard S. Irwin, Rupert C. Barneby

  • Authority

    Irwin, Howard S. & Barneby, Rupert C. 1982. The American Cassiinae. A synoptical revision of Leguminosae tribe Cassieae subtrib Cassiinae in the New World. Mem. New York Bot. Gard. 35, part 2: 455-918.

  • Family

    Caesalpiniaceae

  • Scientific Name

    Chamaecrista diphylla (L.) Greene

  • Type

    Cassia diphylla Linnaeus, Sp. Pl. 376. 1753.—"Habitat in India."—Holotypus, LINN 528/1!

  • Synonyms

    Cassia diphylla L., Cassia cultrifolia Kunth, Chamaecrista cultrifolia (Kunth) Britton & Killip ex Britton & Rose, Cassia diphylla L., Chamaecrista diphylla (L.) Greene, Cassia cultrifolia Kunth

  • Description

    Species Description - Monocarpic or short-lived perennial, the stem either 1 simple erect, or commonly several assurgent or radiating from root-crown, simple or few-branched, at anthesis 1.5-11 dm, the foliage glabrous, glabrous ciliolate, or puberulent, olivaceous or glaucescent; stipules of sect. Xerocalyx 9-25 mm, mostly as long or little shorter than internodes; petiole 3-8 mm; gland 0.4-1 mm diam, sessile or shortly stipitate; lfts 1 pair, in outline varying from obliquely obovate or suborbicular to narrowly oblanceolate, linear-elliptic, or linear, 10-42 x (3-)4-20 mm, when narrow commonly falcately arcuate or dimidiate; pedicels (12-) 15-37 mm; longest sepal ±8-15 mm, the longer petals equalling it or a little shorter; pod 25-52 x 4-7.5 mm; ovules (9-) 12-20.—Fig. 14 (pod, seed).

    Distribution and Ecology - The collective range of Ch. diphylla, including C. cultrifolia, may be summarized: n. periphery of the Caribbean from Cuba through Puerto Rico and Hispaniola to St. Kitts; Mexico, mostly on the Gulf slope (Veracruz to Tabasco and Chiapas) but reaching the Pacific slope in Oaxaca; Central America from Guatemala and Belize to Panama; n.-e. Colombia to Trinidad and the Guianas; middle and lower Amazon valley in Brazil and thence s. over the Planalto to s. Minas Gerais, s.-w. Goiás, and centr. Mato Grosso; Atlantic coastal plain in Rio de Janeiro; formerly introduced in Philippine Is. (Luzon).

  • Discussion

    A survey of the material of Cassia diphylla and C. cultrifolia accumulated at NY before and, particularly, since the last revision (1964) brings home the truth of Bentham’s remark (1870, p. 156) that these species differ only in shape and (weakly correlated) texture of the leaflets. Criteria of pubescence and thickness of leaflet margins (Irwin, 1964, p. 47) are no longer diagnostic of two entities delimited by leaf-shape. Much of broad-leaved C. diphylla from Cuba has ciliolate leaflets, and leaflets glabrous and ciliolate occur in otherwise identical plants in single collections (e.g. Matuda 3793, NY). Thickness of the marginal nerve is an inverse function of the blade’s amplitude, the wider, thinner, more mesophytic type thought proper to C. diphylla having, as expected, a sharper, less corneous edge than that of the narrow, xeromorphic blade of C. cultrifolia. A winnowing by leaf-shape, putting in one pile those with semi-obovate or obliquely obovate blades either straight or convex along the abaxial margin, and in another those with oblanceolate or lunately narrow-elliptic abaxially straight to shallowly concave blades, yields an embarrassingly large residue of intermediates, difficult to assign either way, these in the past having been referred to C. diphylla if prostrate or from Central America and to C. cultrifolia if erect or from Panama or southward. The whole range of variation in leaf-shape seems to follow a unimodal curve, on which the typus of C. cultrifolia is situated close to one extreme, but the typus of C. diphylla only a trifle beyond the mean on the opposing side. The dispersal of the two extreme types is not identical, the broad one alone being found in the West Indies, but extending s. into lower Amazonia and sporadically south in Brazil to Minas Gerais and Mato Grosso, whereas the cultriformis type, dominant on the Brazilian Planalto, extends interruptedly north to Nicaragua (Molina 14882 etc., NY) and southern Mexico (Matuda 3793, already cited).

    The synonym C. pentandria Larranaga, listed in the revision (Irwin, 1964, p. 52) under C. diphylla, is removed with some confidence to Ch. (sect. Chamaecrista) rotundifolia, which better fits the epithet, by being pentandrous, and also the type-locality, which is in or near the city of Rio de Janeiro and not, as surmised, in Uruguay.

  • Distribution

    Cuba South America| Puerto Rico South America| West Indies| Saint Kitts and Nevis South America| Mexico North America| Veracruz Mexico North America| Tabasco Mexico North America| Chiapas Mexico North America| Oaxaca Mexico North America| Guatemala Central America| Belize Central America| Panama Central America| Colombia South America| Trinidad and Tobago South America| Brazil South America| Minas Gerais Brazil South America| Goiás Brazil South America| Mato Grosso Brazil South America| Rio de Janeiro Brazil South America|