TAXONOMY
The Class of

LYCOPODIOPSIDA
Bartl., Ord. Nat. Pl.: 14, 19. Sep 1830

This is based on Arthur Cronquist, 1981-1988.
(The most recent : Angiosperm Phylogeny Group: APG IV, 2016)
Kingdom  Plantae - Plants
   Division   Lycopodiophyta - Lycopods
    Class   Lycopodiopsida
      Order   Isoetales
        Family   Isoetaceae - Quillwort Family                    
            Genus  Isoetes
             Species  caroliniana
      Order   Lycopodiales
        Family   Lycopodiaceae - Club-moss  Family                    
      Order   Selaginellales
        Family   Selaginellaceae - Spike-moss  Family                   
             Genus  Selaginella
             Species  kraussiana Part of Taxonomy Collection

This Class contains around 1000 species, belonging to three Families:

LYCOPODIOPSIDA Isoetaceae Calamaria 26 sp.
  Isoetes app 70 sp
  Stylites 2 sp
Selaginellaceae  Bryodesma 42 sp
  Didiclis sulcata
  Diplostachyum 3 sp
  Hypopterygiopsis reptans
  Lycopodioides app 180 sp
  Selaginella app 680 sp
  Stachygynandrum 2 sp
Lycopodiaceae Austrolycopodium  
  Dendrolycopodium  
  Diphasiastrum  
  Diphasium  
  Huperzia  
  Isoetes  
  Lateristachys  
  Lepidotis  
  Lycopodiastrum  
  Lycopodiella  
  Lycopodioides  
  Lycopodium  
  Palhinhaea  
  Phlegmariurus  
  Phylloglossum  
  Plananthus  
  Pseudodiphasium  
  Pseudolycopodiella  
  Pseudolycopodium  
  Spinulum  
  Urostachys