Macrophyllous cauliflorous shrubs ±3 m, glabrous except for thinly strigulose inflorescence, the foliage subconcolorous, dull olivaceous on both faces, the lfts plane papery, the units of inflorescence compactly racemose. Stipules firm, triangular-lanceolate ±3 x 1.5 mm. Lf-formula i/2½-3½, lf-stk (one seen) ±5 x 3 mm, the nectary immersed; pinnae of unequal length, the rachis of longer one 13.5 cm, the longest interfoliolar segment 5 cm; an immersed nectary at insertion of each pair of lfts; lft-pulvinules 3-3.5 mm; lfts gently accrescent distally, the blades elliptic from inequilaterally cuneate base, shortly acuminate, the distal pair ±15x6 cm; venation pinnate, the subcentric midrib gently incurved, ±8-10-branched on each side, the nerves ventrally immersed, dorsally prominulous. Axis of racemes including short peduncle ±3 cm, the receptacle 7—10 mm, nearly 1.5 mm diam; bracts 0.5 mm, persistent; pedicels 1.5-2.5 x 0.5 mm; perianth 5-merous, finely strigulose overall; calyx shallowly campanulate ±2 x 2.5 mm, weakly 5-nerved, the depressed-deltate teeth ±0.35-0.8 mm, unequal; corolla narrowly claviform ±9 mm, faintly 20 nerved, the lobes nearly 2 mm, recurved at apex; androecium 37-40 mm, ±74-merous, the stemonozone 1.2 mm, the tube 10.5-11.5 mm, the tassel pink; intrastaminal nectary ±1 mm; ovary at anthesis pallid-puberulent. Pods unknown.

In seasonally flooded forest near 200 m, known for certain only from the type locality near 8°20'S, 74°35^/W, in prov. Coronel Portillo of dept. Ucayali in Amazonian Peru. — Not mapped. — Fl. V(-?).

Zygia vasquezii is said in the protologue to differ from itself in short pedicels (2 mm) and strigulose, urceolate-clavate corolla; and from Z. megistocarpa (its nearest relative, even though a member of sect. Macrophylla [not sect. Callozygia]) in the larger corolla (diagnosis). But paradoxically the corolla of megistocarpa was described by Barbosa as 12-14 mm, and that of Z. vasquezii by Rico as 9 mm. Presumably minore should have been majore.

The protologue of Z. vasquezii calls for 5-7 pairs of leaflets per pinna, a slip for 5-7 leaflets. The poor specimen at NY (Rauh-Hirsch PI596), cited as differing only in shorter staminal tube, has only 5 leaflets (not pairs) per pinna. Its identity is doubtful.