Fig. 7: a and b, Pilularia americana: a, habit, showing the filiform bladeless leaves, 

 the young ones coiled, and the stalked sporocarps, x 6; b, sporocarp (cross section), 

 showing the sporangia, x 12. c-e, Isoetes Bolanderi: c, megasporangium on adaxial 

 side of leaf base, the upper part partially covered by the velum, the ligule free, x 3; 

 d, microsporangium on adaxial side of leaf base, the upper portion partially covered 

 by the velum, the ligule free, x 3; e, habit, x %. (From Mason, Fig. 5). 



