“…Owing in part to their small size (1-15 cm) and production of a single, epigeal leaf per year, moonworts exhibit a remarkable degree of morphological simplicity and possess a limited number of characters for delimiting species and constructing classifications. Using morphological features, Clausen (1938) recognized only six species in subgenus Botrychium, whereas W. H. and F. S. Wagner and others have raised that number to ϳ24 species based on a combination of morphological and cytological studies (F. S. Wagner, 1993;Wagner and Wagner, 1981, 1983a, b, 1986, 1990a, b, 1994Wagner et al, 1984;Farrar and Johnson-Groh, 1991; see Table 1, Figs. Clausen, 1938;Tryon and Tryon, 1982;Wagner and Wagner, 1993).…”