Monographs Details: Senna birostris var. totorae 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 1: 1-454.
Description:Variety Description - Bushy shrubs 1-4 m, the young branchlets, lf-stalks and axes of inflorescence strigulose-pilosulous with pallid or lutescent hairs ±0.2-0.4 mm, the dull olivaceous lfts glabrous above, slightly paler beneath, ciliolate; stipules linear or narrowly lanceolate 3-6.5 x 0.5-0.8 mm; lvs (4-)5-13 cm; petiolar gland at or just above proximal pair; lfts 6-9 pairs, on pulvinules (0.7-) 1-2.2 mm, in outline oblong-elliptic, -ovate, or elliptic-obovate, the longest 14-30 x (5-)6-12 mm, 2-3.4 times as long as wide, veinless above, the dorsally prominent midrib giving rise to 6-9 pairs of fine discolored but immersed secondaries; racemes (7-) 10-40- fld; sepals well graduated, the outer 2.5-3(-4) mm, the inner 4.3-5.5(-6) mm; petals 6-11.5 mm; filament of 2 latero-abaxial stamens 2.3-3.5 mm, their anther 3.5-4.6 mm, the centric abaxial stamen 0 or staminodal, the sterile linear anther ±2-2.5 mm; ovary pilosulous; style 0.8-1 mm; ovules 15-18; stipe of pod 2.5-3 mm, the body ±4 x 0.9 cm.—Collections: 7.—Fig. 26. [Key: "Anthers of 2 lateral abaxial stamens fertile and 2.4-3.5 mm long, that of the centric one much smaller and sterile or the stamen absent; style 0.8-1 mm; e. edge of Bolivian altiplano in Cochabamba and Potosi."]

Distribution and Ecology - Rocky hillsides, sometimes colonial on road-cuttings, 2000-2800 m, locally frequent on Cordillera de Cochabamba and extending s. to the head of Rio Pilcomayo, e. margin of Bolivian Altiplano in Cochabamba and Potosi (lat. 17°20'-19°30'S).—Fl. IX-III(-V).

Discussion:Within its species var. totorae stands alone in the obsolescence or full suppression of the centric abaxial stamen, in the small size of all six fertile anthers, and in the abbreviated style, and it is these features of the corolla which alone distinguish it from all of var. hookerana. From Peruvian var. huancavensis it differs further in the fewer (6-9, not 10-14) pairs of leaflets, the glabrate flower-buds, shorter inner sepals (4.3-6, not 7.5-10.5 mm) and in the shorter, short-stipitate pod. Habitally similar but less closely related S. aymara, actually or nearly sympatric with var. totorae in Cordillera de Cochabamba, may be separated at anthesis by the broader stipules, sepals of subequal length and the presence of three fertile abaxial stamens, and when in fruit by the sharply defined areole on each face of the seeds.
Distribution:Cochabamba Bolivia South America| Potosí Bolivia South America|