Humifuse, 1.5-4 dm, puberulent and sparsely setulose; adult lvs 1-2 cm; gland 0.15-0.2 mm diam, 0.3-0.45 mm tall, the stipe filiform; lfts 5-8 pairs; peduncles obsolete, 2-fld; pedicels at anthesis scarcely evident, becoming 0.5-1 mm long in fruit; sepals 2.6-3.1 mm; petals 2.4-3 mm, 4 alike and ± 1.4 mm wide, the cucullus scarcely differentiated; style 0.5 mm; stamens 3-5, the long anthers up to 1.1-1.3 mm; pod as described in key, the valves thinly pilose.—Collection: 1 (typus).

Habitat not recorded, but to be sought in savanna on sandy ground, probably near 100 m, known only from the type-locality, surmised to be San Jeronimo Ixtepec on the Isthmus of Tehuantepec railroad n. of Juchitán.

A remarkable little plant, with all essential characters of C. calycioides but too far modified in its diminished flower, depauperate androecium and abbreviated pod to be classed among the minor variants of var. calycioides described above. The small pod might suggest a history similar to that of Chamaecrista tabascoensis, which we have interpreted as a drought-modified C. nictitans var. diffusa, the short pod of which becomes few-seeded only by abortion of several ovules. The three complete plants of var. lentiformis which form the type-series are in full vigor of anthesis and early fruit, and two dissected ovaries contained 2 and 3 ovules respectively, no more numerous than the maturing seeds. We assume that var. lentiformis arose as a mutation from var. calycioides which also occurs, but rarely, on the Isthmus lowlands.