The problem is that, currently, Agave parryi var. truncata is considered a synonym of Agave parryi subsp. parryi which is why you see those plants here...the database here goes with the most currently available taxonomic classifications, within reason as things change all the time. Our main source for reference is the Catalog of Life, but we do refer to other sources for more specific details at times.
http://www.catalogueoflife.org...
