Monographs Details: Chamaecrista cuprea H.S.Irwin & Barneby
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
Description:Latin Diagnosis - Chamaecrista cuprea Irwin & Barneby, sp. nov., notulis multis cum afflni Ch. pascuorum congrua sed ab ea statura pumila, stipulis parvis 1.6-2.2 (nec 4.5-10) mm longis ±5-7 (nec 8-13)-nerviis, foliis abbreviatis minus quam 2 (nec 2.5-7) cm longis, foliolis plerumque 3 (nec 4-9)-jugis, necnon floribus leguminibusque minoribus, his ±2.5-3.5 (nec 4-7.5) cm longis 8-10 (nec 14-28)-ovulatis diversa.—BRAZIL. Bahia: Lagôa Itaparica, 10 km w. of the São Inácio-Xique-Xique road at turning 13.1 km n. of São Inácio, 42°46'W, 11°01'S, 26.II.1977 (fl, fr), R. M. Harley 19123.

Species Description - Dwarf microphyllous subshrubs 1-2 dm, with gnarled contorted blackish caudex and stiff, sparsely leafy incurved-ascending, simple or few-branched annotinous branchlets, the young stems, lf-stalks, sepals and ovary puberulent with fine appressed pallid hairs up to 0.1-0.2 mm, the foliage bicolored, the carnosulous lfts dark blue-green glabrous above, glaucescent but either glabrous or puberulent beneath. Stipules erect, ovate-, triangular- or lance-acuminulate 1.6-2.2 x 0.7-1.2 mm, the often eastaneous or purplish blades coarsely 5-7-nerved from asymmetric base, persistent. Lvs 6-17 mm, the expanded blade ovate in outline; petiole including wrinkled pulvinus 1.5-3.5 mm; rachis (l-)2-6(-7.5) mm; gland inserted immediately below proximal pair of lfts stipitate, in profile slenderly peg-shaped 0.3-0.6 mm tall, at apex scarcely dilated, the concave head 0.2-0.25 mm diam; pulvinules 0.2-0.4 mm; lfts 2-4, in most lvs exactly 3 pairs, of subequal size or the penultimate pair slightly longer and broader than the rest, all in outline obliquely oblong-obovate or oblong, obtuse mucronulate or obscurely acuminulate, the larger pairs 2.5-7 x 1-4.5 mm, ±1.5-2.7 times as long as wide, all at base cordate on proximal and rounded on distal side, the blade 3-4-nerved from pulvinus, the moderately displaced midrib giving rise to (2-)3-4(-5) pairs of secondary veins, these all immersed above, bluntly prominulous beneath. Peduncles adnate to stem through (1-) 1.5-6 mm, 1-2-fld, the axis not over 1 mm; pedicels 5-11 mm, bracteolate 1-3 mm below calyx, incurved-ascending in fruit; fl-buds slenderly ovoid-acuminate puberulent; sepals narrowly ovate or lanceolate acute, delicately nerved from base, greenish-yellow or red-tinged, 7-9.5 mm; petals when fresh "dark reddish-orange with yellow margin," when dry livid pallid-edged, highly heteromorphic, the vexillary one and one adjacent petal smallest, semi-ovate beyond short claw, ±8-11 mm, one lateral and one abaxial petal larger, subsymmetrically obovate-flabellate 12-14 mm, the boomerangshaped cucullus a little longer, 14-16 mm, incurved over androecium; androecium 10-merous 2-cyclic, the filaments of 5 outer stamens 1-1.4 mm, of 5 inner ±0.5 mm, the slenderly lanceolate anthers of outer cycle 5-6.5 mm, of inner cycle ±4 mm; style glabrous almost straight 5.5-7 x 0.25-0.3 mm; ovules 8-10. Pod ascending linear 2.6-3.3 x 0.35-0.4 cm, the greenish valves red-margined; seeds compressed-rhomboid ±3.3 x 2 mm, the testa fuscous, sparsely pitted.— Collections: 1.—Fig. 48.

Distribution and Ecology - Open sandy places ±300-400 m, known only from the type-locality near 11°S in w.-centr. Bahia.—Fl. I—III.

Discussion:

A singularly attractive chamaecrista, notable for the wiry fruticulose habit, neat glaucescent foliage and proportionately large flowers that open rich orange margined with yellow and do not simply acquire (like many kindred) an orange flush as they fade. Striking as the flower color may be, it is not reliably diagnostic, for we have random instances of orange petals (cf. Mori 9513, CEPEC, NY) in populations of the closely related and sympatric Ch. pascuorum. The latter, widely dispersed through highland central Bahia and very likely the immediate progenitor of Ch. cuprea, is highly variable in detail but is consistently of coarser growth, with larger leaves and stipules, coarser petiolar glands, more numerous and longer leaflets, and especially a longer pluriovulate pod. It seems possible that Ch. cuprea, as known to us from only one population, represents merely an extreme and emphatic variant of Ch. pascuorum fated to be reabsorbed into the main genetic current of that species; but for the present the number and quality of differences, emphasized in the key and implicit in the descriptions, leave no alternative to treating it as an independent species.

Distribution:Bahia Brazil South America| Brazil South America|