(from the article `plant`) ...genera and between 600 and 1,000 species; representative genera include Lycopodium, Selaginella, and Isoetes.Division Psilotophyta (whisk ... Psilotophyta (whisk ferns) is a division represented by two living genera (Psilotum and Tmesipteris) and several species that are restricted to the ... [2 related ...