Selaginella arenicola

This record represents the narrow concept of Selaginella arenicola at the species level, according to Clausen (1946). In contrast, FNA (1993), Kartesz (1994), and Kartesz (1999) treat it as a subspecies of S. arenicola.

Note: The distribution map in Clausen (1946) is mislabeled as S. acanthonota.

The Selaginella arenicola complex, comprising S. acanthonota, S. arenicola, and S. corallina, has been treated variably at the species, subspecies, and variety levels. Modern treatments (e.g., Zhou and Zhang 2023 and Weakley and the Southeastern Flora Team 2025) include all three taxa at the species level, though in the genus Bryodesma. However, FNA (1993, vol. 2) and the Pteridophyte Phylogeny Group I (2016) recognize the family Selaginellaceae with a single genus, Selaginella. Attempts to recognize subgenera (e.g., six in Zhou and Zhang 2015, seven in Weststrand and Korall 2016) lack consistency, and the elevation of subgenera to nineteen genera in Zhou and Zhang (2023) has mixed acceptance. While Weakley and the Southeastern Flora Team (2025) treat their fifteen taxa in four genera, Valdespino et al. (2024) provide justification to conserve Selaginellaceae in a single genus with approximately 750 taxa, which the World Flora Online (2025) accepts, following the Pteridophyte Phylogeny Group.