Chamaecrista supplex

Very slender, sometimes diminutive, humifusely matted herbs of short duration, precociously flowering and then appearing annual but in age ± lignescent at base, with 3-several simple or few-branched, pliantly flexuous, densely leafy stems 0.4-3.5 dm radiating from the root-crown, the stems except for some faint lines of short incurved hairs commonly glabrous, but the stipule margins, lf-stalks, and dorsal face and margins of lfts ± densely pilose or pilosulous with fine white spreading and straight or widely incurved-ascending septate setae to 0.6-1.3 mm, the foliage olivaceous or brownish, concolorous, the tiny axillary short-pedicelled fls often concealed by lvs.

Stipules erect, appressed to stem, persistent, bluntly deltate-ovate-caudate or -acuminately aristate from an asymmetrically cordate-amplexicaul base, 2.4-5 x 1.3-2.6 mm, from base prominently (5-)7-9(-ll)-nerved, the lateral nerves incurved distally into a marginal one, the blades submembranous between veins.

Lvs obliquely ascending toward the meridian, petioled, 9-22 mm, the expanded blade ovate in outline; petiole 2.5-4 mm, narrowly margined and open-sulcate; gland shallowly cup-shaped reddish, 0.2-0.35 mm diam, elevated on a slender stipe 0.25-0.5 mm; rachis 3.5-10 mm; lfts (3-)4-5, of most adult lvs exactly 5 pairs, when expanded the first pair divaricate from rachis and the succeeding ones pitched forward at progressively sharp angles, the terminal pair ascending from rachis side-by-side, all in outline obliquely oblong to dimidiately obovate, a trifle forwardly incurved, obtuse but abruptly mucronulate, at base semicordate on proximal side, the blades firmly membranous, the weakly penniveined, moderately excentric costa accompanied from pulvinule on broad side by 2-3 and often on narrow one by 1 incurved-ascending veins, these all sharply prominulous beneath, less so above.

Peduncles exactly axillary, 0-1 mm, 1—2-fld; pedicels 2.5-6.5 mm, bracteolate near and above middle, at anthesis ascending, in fruit firm, sigmoidally divaricate; buds narrowly ovoid acute, pilosulous; sepals membranous, pale green or reddish- tinged, at anthesis widely spreading to deflexed, narrowly ovate to lance-elliptic acute, 3.1-4.1 mm; petals yellow early fading orange or purplish-orange, sub- marcescent, 4 narrowly oblanceolate to spatulate-obovate, narrowed downward into a slender claw, unequal, 2 smaller up to 1.7-3.3 mm, 2 larger up to 2.8-4 mm, the cucullus dimidiately obovate or broadly ear-shaped, 3.5-4.9 mm, not over 1 mm longer than sepals; stamens 3-5, at most 3 fertile and the 2 accessory, if present, minute and sterile, the 2-3 fertile with linear-oblong or shortly oblong anthers to 1.2-1.9 mm, the largest that directly opposed to the divaricate gynoecium; ovary densely white-pilose; ovules 2-5; style 1.5-2 mm, incurved to bring the stigma almost to quite in contact with the large contiguous anther.

Pod narrowly or, when very short, broadly oblong in outline, 4-13 x 2-3 mm, tipped by the short, incurved style-base, the castaneous valves densely pilose with fine flexuous white setae to 1—2.6 mm; seeds quadrate or prismatically compressed-pyriform, 1.2-2.3 mm, the testa pale pinkish-ochraceous with faint black line along the distal keel, sublustrous, rugulose, faintly pitted, mucilaginous when wetted.—Collections: 31.—Fig. 46.

Campo, open places in cerrado and capoeira, and caatinga, sometimes weedy along highways, usually in thin, especially sandy soils, (20-) 150-950 m, local, scattered over e. Brazil from middle Tocantins valley in s.-w. Maranhão e. to Ceará and the lower S. Francisco valley in w. Pernambuco and adjoining Bahia, s. through e. Goiás and w. Bahia to Distrito Federal; e.-centr. Bahia (Ibicaraí; doubtfully recorded from s. Minas Gerais (Glaziou 12614, P); disjunct on dry campo of the lower Amazon valley near Montealegre, Pará; and on the Atlantic coast of s.-e. Rio de Janeiro (Paratimirím); reported (Britton & Killip, 1936, I.e.) erroneously from Colombia.—Fl. II-VI.

The smallest of the prostrate Brazilian chamaecristas, Ch. supplex is readily distinguished from sympatric small-flowered forms of Ch. serpens var. serpens by the cordate stipules, broader more obtuse leaflets, short pedicels and an androecium reduced to at most five members, only two or three of them bearing fertile anthers. In habit and in details of foliage and stipules Ch. supplex resembles, and in consequence has been confused with, Ch. cordistipula, which is, however, easily distinguished by its large, probably out-crossing, long-styled flower. Bentham drew attention to the uncinately recurved style-base that tips the small pod of Ch. supplex and contrasted it with the straightish style-base of Ch. cordistipula. The difference in this tiny organ has become blurred by modem collections.