A new species of gemmiferous clubmoss, Huperzia continentalis, is described. This species is most abundant in northwestern North America, but also occurs in Greenland, northern Europe, and northeastern Siberia. Material of this species was previously treated as Huperzia haleakalae, but detailed morphological study shows that the species differ by color, leaf size and shape, and gemma distribution. With the recognition of Huperzia continentalis, H. haleakalae is only known from the type, collected on Maui in 1840, and is likely extinct. Huperzia continentalis is also compared to similar species of Huperzia with which it co-occurs; it is readily distinguished from these taxa by plant size, leaf dimensions, and the size and distribution of gemmae. Hybrids between H. continentalis and four other Huperzia species are discussed.