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Selaginella

There 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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  S. selaginoides
  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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  S. rupestris
  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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  S. apoda
  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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  S. eclipes
  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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Show photos of: Each photo represents one species in this genus.