Which genus has more species, Psilotum or Austrocylindropuntia?
Psilotum:  There are only two species in "Psilotum" and a hybrid between the two. Austrocylindropuntia: Austrocylindropuntia is a genus of cacti (family Cactaceae) with 11 recognized species, which were once included in the genus "Opuntia".
Austrocylindropuntia