Monographs Details: Senecio yapacanus Aristeg.
Authority: Maguire, Bassett & Wurdack, John J. 1957. The Botany of the Guiana Highland -- Part II. Mem. New York Bot. Gard. 9 (3): 235-392.

TYPE: Vine, flowers white, occasional in cumbre, elev. 1200 m, Cerro Yapacana, Terr. Amazonas, Venezuela, Jan. 3, 1951, Bassett Maguire, Richard S. Cowan & John ]. Wurdack 30719 (NY). Paratype: Woody vine, occasional on west escarpment face, elev. 1800 m Cerro Huachamacari, Terr. Amazonas, Venezuela, Dec. 14, 1950, Maguire, Cowan & Wurdack 30232.

This new species is related to S. oronocensis DC. from the Bolivian Andes; it differs by its scarcely arachnoid-lanose leaves never completely covered by white tomentum on the lower surfaces and its completely glabrous involucral bracts. The bracts of S. oronocensis are covered by a brown lanose tomentum. S. oronocensis was described from a Haenke collection, since credited to Venezuela. Dr. Cuatrecasas, however, informed me that the original locality was Bolivia or eastern Peru and that S. baccaradiflorus Rusby is a synonym of S. oronocensis.