Our three small species are not easy to find, looking rather moss-like. The majority of specimens were probably found while looking for something else. Like Isoetes, these have both large spores (megaspores) and tiny microspores. Fortunately, spores are not needed for identification.
1. Leaves with a short, scabrous bristle at the apex (this wearing off in older leaves); shoots squarish; plants of dry sandy or rocky sites.
1. Leaves acute to long-acuminate, the apex not bristle-like nor scabrous; shoots flattened or round in cross section; plants of moist to wet habitats.
2. Leaves minutely many toothed, acute; plants with fertile portions spreading.
2. Leaves with a few scattered large, spreading, bristle-like teeth, acuminate; plants with erect fertile stems.
All species found in Selaginella
MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. December 11, 2017. http://www.michiganflora.net/genus.aspx?id=Selaginella.