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Selaginella
See list of 4 species in this genusThere exist two distinct and monophyletic lineages within the Selaginellaceae that could be recognized as genera. One lineage includes the species that lack rhizophores and have terete strobili ( Selaginella sensu stricto). The other lineage contains species with rhizophores and tetragonous strobili ( Lycopodioides). However, several nomenclatural issues stand in the way of dividing Selaginella. Reference: Valdespino (1993).
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1a. Trophophylls monomorphic, spirally arranged, not in distinct ranks [Fig. 16]; axillary trophophylls absent at branching points
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2a. Trophophylls thin, spinulose-toothed, acuminate, with stomates scattered over the abaxial surface; strobili terete; sporophylls ascending to spreading, mostly 10-ranked [Fig. 16]; rhizophores absent
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2b. Trophophylls thicker, ciliolate, bristle-tipped, with stomates restricted to an abaxial groove; strobili tetragonous; sporophylls appressed, 4-ranked; rhizophores present
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1b. Trophophylls dimorphic, arranged in 4 ranks, the 2 lateral ranks with larger leaves than the 2 median ranks [Fig. 15]; axillary trophophylls present at branching points
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3a. Median trophophylls acute to acuminate at apex, rarely attenuate and then often apically keeled and the vein not reaching tip; megaspores 0.29–0.35 (–0.38) mm in diameter, closely reticulate, dull
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3b. Median trophophylls with a long-attenuate, often recurved, apex, not keeled, the vein prolonged into the tip; megaspores 0.33–0.4 mm in diameter, more loosely reticulate, shiny
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Each photo represents one species in this genus.