Explanation from Kelly Allred's Flora Neomexicana II: "Turner’s original epithet (maryannum, in Centaurium) was ill-formed, and should have been either maryannianum (adjectival form) or maryanniae (substantival form) (see Article 60.8, International Code of Nomenclature). Subsequent authors have all (except one) used the corrected adjectival epithet maryanniana or maryannianum."