Monographs Details: Senna pallida var. delgadoana 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.
Description:Variety Description - Subarborescent, the annotinous branchlets gray lenticellate, the young ones and the foliage loosely strigulose, the lfts bicolored, dull olivaceous above, pale beneath, the inflorescence composed of solitary or paired axillary 1-2-flowered racemes. Stipules erect linear-setiform deciduous. Lvs 6-10 cm; petiole 11-15 mm; rachis 3-8 cm, the longer interpetiolular segments 3-6 mm; gland between proximal pair 2-2.3 mm, oblanceolate compressed acute, and a gland at tip of rachis collateral with the seta; lfts (7-)9-24 pairs, narrowly elliptic or elliptic-oblanceolate, the longer ones (near middle of rachis) 14-20 x 3-6 mm, 3-4 times as long as wide, the margin revolute, the upper face veinless, the midrib prominent beneath and 5-8 pairs of secondary veins discolored but immersed. Peduncles 5-9 mm; fruiting pedicels ±1 cm; stipe of pod 5-6 mm; body linear (4.5-6-11 x 0.6-0.9 cm, the valves a little elevated over the seeds but not decussately ridged; seeds 16-22, paddle-shaped 3.5-4.5 x 3-4 mm, the areole 1.3-2 x 1 mm.-Collections: 3. [Key: "Appendage terminal of lf-stalk modified into a gland resembling that between proximal pair of lfts; local either in highland centr. Costa Rica or in s. Mexico (Mexico, Oaxaca, Veracruz). Lfts of larger lvs 14-24 pairs and not over 2 cm long; ovules 16-22; pod 6.5-11 cm long; highland n.-w. Oaxaca at 1530-1700 m."]

Distribution and Ecology - Oakwoods, 1530-1700 m, locally plentiful but known only from the vicinity of Copala, distr. Juxtlahuaca, Oaxaca.-Fl. I-II, fr. VIII.

Discussion:The var. delgadoana, marked by the combination of many pairs of relatively small, revolute, simply penniveined leaflets, a gland between the distal pair collateral with the seta, and a short few-seeded pod, has a notably distinct facies and perhaps deserves specific status. We dedicate it to Dr. A. Delgado S., a perceptive student of Cassieae and Mexican legumes in general.
Distribution:Oaxaca Mexico North America|