Yucca filamentosa and Yucca flaccida (Agavaceae) Are Distinct Taxa in Their Type Localities

ABSTRACT There has been question whether the taxon known as Yucca filamentosa (Agavaceae) is to be distinguished from the taxon known as Yucca flaccida. Much of the uncertainty lay in the absence of sure knowledge of the forms intended by their original authors. A neotype of Y. flaccida from Florida was selected in 2006. Here, the type locality in Virginia of Y. filamentosa is revisited and an epitype is selected. The two taxa, as represented by plants from these two type localities, differ markedly in a number of characteristics. It is suggested that Y. filamentosa and Y. flaccida be retained at specific rank.