Selaginella apoda, commonly known as meadow spikemoss, is a perennial lycophyte native to much of the eastern United States and parts of northeastern Mexico. The life cycle is the shortest of the Selaginella genus, as well as one of the shortest among the lycophytes. Selginella apoda is found primarily in damp soils in habitats such as swamps, wet fields, open woods and along stream banks. Selaginella apoda presents the potential for case studies involving the plant’s adaptability to environmental toxins. A lowland plant, it has only been recorded at elevations below 100 meters. It is closely related to Selaginella eclipes and S. ludoviciana, both of with which it has been reported to form hybrids. This group is characterized by relatively flat strobili and large megasporophylls which occur in the same plane as the lateral leaves.

The plant was originally described, and named Lycopodium apodum by Carl Linnaeus in his Species Plantarum (1753).