This poorly understood taxon is apparently extinct. Cabrera, I believe, uses "acuminate" as akin to "apiculate" or "caudate" where Mez meant "attenuate" without abrupt transition. This conclusion would relate it closely to the typical variety as Cabrera has it and farthest from the Brazilian variety angustior where I used "acuminate" in Mez's sense. Variety tandilensis represented the southernmost extension of the genus. —SeeSmith & Downs 1974
