Selaginella was hyperdiverse already in the Cretaceous.

The spike mosses (Selaginella P.Beauv.; c. 750 species) are not only the most speciose extant genus of lycophytes, but also one of the largest land plant genera (Jermy, 1990). In addition to the exceptionally high number of living species it comprises, Selaginella is an ancient lineage believed to date back to the Carboniferous or even Devonian based on fossil evidence (Kenrick & Crane, 1997; Thomas, 1997; Korall et al., 1999; Taylor et al., 2009) and DNA-based divergence time estimates (Klaus et al. 2017; Morris et al. 2018).