Monographs Details: Senna racemosa var. sororia 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.
Family:Caesalpiniaceae
Description:Variety Description - Foliage densely loosely pilosulous with hairs up to 0.4-0.8 mm, the vesture of lvs gray or yellowish, of inflorescence rusty-fuscous; lvs 11-26 cm; lfts 9-12 pairs, the largest 2.3-5.4 x 1-2.6 cm, either elliptic or obovate, obtuse or deltately acute, the secondary veins 5-7 pairs, fully immersed above, prominulous beneath, the tertiary reticulation faintly prominulous beneath only or merely discolored; outer sepals 4-7 mm, inner ones 6.5-10 mm; long petals ±15 mm; androecium of var. liebmannii, the anthers sparsely pilosulous distally with weak hairs ±0.5-0.7 mm; ovary densely rusty-pilosulous; style glabrous 2.5-4 mm; body of pod (little known) 13-18 x 1.1-1.3 cm, the seed locules 6-7 mm long.-Collections: 9. [Key: "Ovary and pod densely rusty-pilosulous; pinnate venulation of lfts prominulous beneath only and tertiary venulation of both faces fully immersed; s. Mexico (s.-w. Mexico to Chiapas). Lfts of larger lvs 9-12 pairs; s.-e. Mexico, Morelos and adjoining Guerrero."]

Distribution and Ecology - Ipomoea-thorn-forest and brush-grassland transition in the hill country around the n.-e. margin of Balsas Depression at ± 1100-1600(-2100) m, local, s.-w. Mexico (mun. Tejupilco and Ixtapan de la Sal), Morelos (mun. Yautepec, mun. Jiutepec) and n.-centr. Guerrero (mun. Chichihualco, mun. Zumpango del rio, mun. Taxco), ±99°-100°20'W, 17°30'-19°S, in s. Mexico.-Fl. X-III.

Discussion:Hinton’s collections of var. sororia from Temascaltepec District were determined at Kew as Cassia liebmannii and C. andrieuxii, at the time the most nearly appropriate alternatives. The variety is related to both, but different in the numerous pairs of leaflets, in this respect approaching the more northern and western, fully and distantly disjunct populations that we have described above as var. moctezumae and var. coalcomanica respectively, both distinguished by their glabrous pistils.
Distribution:México Mexico North America| Morelos Mexico North America| Guerrero Mexico North America|