Senna trichosepala (Chodat & Wilczek) H. S. Irwin & Barneby (1982: 570) .

Cassia aphylla var. trichosepala Chodat & Wilczek (1902: 475) . Cassia trichosepala (Chodat & Wilczek) Bravo (1978: 373) . Type:— ARGENTINA. Mendoza: Dep. San Rafael, San Rafael, des les tables. Plantes des environs de St. Rafael et de la Vallée du Rio Atuel, Wilczek 93 (holotype, US).

Cassia fabrisii Bravo (1978: 377) . Senna fabrisii (Bravo) H. S. Irwin & Barneby (1982: 370) . Type:— ARGENTINA. San Juan: Dep. Iglesia, 10km de Pismanta hacia Rodeo, R. Palacios & L. Bravo 593 (holotype, SI!; isotype BAFC!), syn. nov.

Shrubs 0.8−3.0 m tall; branches glabrous to silky at the base, hairs to ± 5 mm long, erect-ascending, divergence angle 30º−70º; leaf 0.5−1.0 mm long, 0.5 mm wide. Bracts 1.0− 1.5 mm long, 0.25−0.75 mm wide; peduncle 2−19 mm long, 0.25−0.75 mm wide; pedicel 4−16 mm long, 0.25−0.75 mm wide, both the peduncle and pedicel both glabrous to densely pubescent. Calyx glabrous to densely pubescent, the 2 smaller sepals 4−7 mm long, 2−4 mm wide and the 3 larger sepals 6−8 mm long, 4−6 mm wide. Petals 7−22 mm long, 4−12 mm wide. Androecium: 3 anthers of long abaxial stamens 4.0− 6.5 mm long, and filament 1.5−11 mm long; 4 anthers of median stamens 3−4 mm long, and filament 1−2 mm long and 3 staminodials 1−2 mm long, and filament 1−3 mm long. Gynoecium 10−12 mm long, 0.75−1.0 mm wide, glabrous to densely pubescent. Pods 7.3−12.2 mm long, 4.0− 5.5 mm wide, glabrous to sparsely pubescent. Seeds 3.5−4.5 mm long, 3.0− 3.5 mm wide.

Distribution:— Catamarca, La Rioja, Mendoza, San Juan and San Luis provinces in the central and western area of Argentina. Inhabiting rocky and sandy soils.

Additional specimens examined:— ARGENTINA. Catamarca: Belén, pendiente de Belén, entre Andalgaláy Belén, 24 January 2005, Barboza 1146 (CORD); La Rioja: Arauco, en el monte, 22 March 1944, Hunziker 5101 (CORD); Chilecito, 7 April 1906, Stuckert 15742 (CORD); Hunziker 4282 (CORD). Entre San Miguel y Malingasta, February 1962, Dawson 3384 (CTES); Independencia, Cueva del Chacho, entre Patquía y Los Colorados, 30 November 1961, Cocucci 367 (CORD) ; 30 km al noroeste de Patquía, 5 February 1973, Hunziker 9508 (CORD); Mendoza: Las Heras, Salangasta, 21 December 1991, Lutz 106 (CTES); Uspallata, 20 December 1949, Barkley 815 (LIL); 22 km al sur de Tucunuco, 30º 51´S 68º 37´W, 7 March 2011, Fortunato 9914 (BAB); 12 km al este de Rodeo, sobre ruta nacional 150, 30º 12´S 69º 02´W, 20 January1997, Fortunato 5564 (BAB); 25 de Mayo, 12 km al este de Encon, sobre ruta nacional 20, 32º 12´S 67º 40´W, 6 March 2011, Fortunato 9913 (BAB) .