In our previous comment dedicated to the genus Tunilla D. Hunt & Iliff (Anceschi & Magli 2013a, 87-88), of the 12 initial species considered by the authors of the genus (Hunt & Iliff 2000, 9: 8-12), we had circumscribed two only, the recognition of taxa at a specific level, i.e. Tunilla corrugata (Salm-Dyck) D. R. Hunt & Iliff and Tunilla soehrensii (Britton & Rose) D. R. Hunt & Iliff. This is due to the difficult distinction, both morphologically and territorially, of the species in their natural habitats (as already highlighted by Kiesling & Ferrari (2005, 29); underlining that in some points of the areas occupied by the two species, there seem to exist merging points. The judgment on the recognition of a third possible taxon, namely Tunilla erectoclada (Backeberg) D. R. Hunt & Iliff, at that time for us not clearly attributable to the two accepted taxa, remained pending. Subsequent investigations carried out in 2013 in Argentina, Catamarca Province, El Rodeo, revealed scattered populations (A&M 866) showing the characters of T. erectoclada (see Anderson 2001, 664). In fact, the individuals in question show stem segments narrow, tongue shaped, erect in young growth, distinctly tuberculate, bright green (photo 06); areoles as many as 140 per segment, spines 4-7, from bent backward and lying next to the surface, to many, spreading (photos 05-06); flowers carmine red (photos 02-03, 06-08). We therefore add T. erectoclada as a third taxon to our understanding of Tunilla. (Quoted from Anceschi & Magli 2021, 84)