A Conspectus of the North American Isoetaceae

Abstract

Inscrutable, complex, and important, quillworts (lycophyte genus Isoetes) have bedeviled and fascinated field botanists for over 150 years. An outwardly simple appearance belies the internal intricacies that distinguish individual species. North American species occur in a wide variety of wetland habitats, ranging from tidal flats to subalpine lakes. Over 30% of the continent’s known species are regional endemics and their sensitivity to environmental stresses has resulted in many being of regional or even global conservation concern.