"The term 'taxa' (singular, 'taxon') designates described plant entities and may be used as an alternative to 'species' when there is sufficient disagreement among taxonomists as to whether the plant is a true species or not. If not widely accepted as a distinct species, the plant may be considered a 'variety' or 'forma,' but all such units of identity are still taxa." — Ron Lance, Woody Plants of the Southeastern US, A Winter Guide