Senna pallida var. nemorosa

Weakly arborescent, at anthesis 1-2.5 m, sparsely pilosulous with subap- pressed hairs to 0.3-0.5 mm, the lfts glabrous on both faces, the inflorescence and general facies of var. pallida.

Stipules subulate-setiform 1.5^ x ±0.2 mm.

Primary cauline lvs 3.5-9(-10) cm; petiole 5-15 mm; rachis 2-7 cm; gland sessile or short-stipitate, 2-2.6 x 0.5-0.9 mm; lfts (5-)6-9 pairs, oblong-elliptic or obovate, not or only slightly accrescent distally, the largest 8-18 x 5-9 mm, the pinnate venation finely prominulous above, reticular venulation 0.

Peduncles 1.2-3 cm; pedicels 15-20 mm; large sepals 6-8.5 mm; long petals 16-22 mm; 4 median anthers ±4 mm, with pronounced conic points at the truncate apex, the 3 abaxial ones 4.5-5 mm with beak 1.8-2.5 mm.

Stipe of pod 5-6 mm, the body 6-11 x 0.6-0.75 cm; seeds oblong or obovate in profile 3.9-4.5 x 1.8-2.5 mm, the areole 0.45-0.6 x 0.4-0.5 mm.-Collections: 10.

Xeromorphic scrub-thickets and algarrobal, 400-800 m, highly localized in the middle Maranon valley, lat. 5°35'-5°50'S, in Cajamarca (e. prov. Jaen) and adjoining Amazonas (prov. Bagua), Peru.-Fl. III, VI, X, perhaps intermittently through the year.

The var. nemorosa is greatly isolated geographically from the rest of its species, its compact range lying some 750 km distant from the southernmost outpost of var. pallida in southern Colombia. In general appearance and in details of the simply penniveined leaflets and the broad pod it very closely mimics the Mexican var. palmeri, from which it differs feebly in the shorter petioles, smaller corollas and larger seeds with a proportionately much smaller aerole on either face. Mac- bride (1943, p. 158), following Bentham (1871), included this endemic Peruvian senna in a comprehensive Cassia biflora. The specimens from Lima and Ancash, however, that Macbride refers to C. biflora actually represent the related Senna incarnata.