Agave americana subsp. protamericana Gentry Agave americana subsp. protamericana Gentry, Agaves Cont. N. Amer.: 287, f. 12.1-12.5, 12.8, 12.12, 12.14 y 12.15, t. 12.1. 1982 sec. Espejo-Serna & López-Ferrari 2008