Tigridia potosina (Iridaceae: Tigridieae) una nueva especie de la Sierra de Álvarez, San Luis Potosí, México

Tigridia potosina, a new species discovered in the Sierra de Alvarez, San Luis Potosi, Mexico, is described and illustrated. The new species belongs to subgenus Hydrotaenia and is morphologically similar to Tigridia multiflora (Herb.) Ravenna but is distinguished by the size and the color of tepals, and by the width of the floral cup. Also the new species may be confused, because of the flower color, with T. alpestris Molseed ssp. obtusa Molseed, but differs from that taxon in the form of tepals and in the larger style branches.