Every single grower of Agave parryi var. truncata who has seen the other varieties would disagree, and I am happy to note that in a comment. I would like to invite anyone to point out a scientific source where var. truncata was placed in synonymy with ssp. parryi. Through its recorded history the plant has been separate and distinct from other known varieties of the plant. Let me put this differently. If var. huachucensis and var. couesii and not part of ssp. parryi (only truncata is allowed), then they must be part of another ssp. within the genus (which does not exist and has never existed that I've heard of).
