Notes: Hortus III says 20 or more species, Gleason & Cronquist use 50 species; but RHS uses 70, and European Garden Flora uses 65. However, RHS includes Rhoeo in Tradescantia as Tradescantia spathacea.
Hortus III and others indicate that most plants in gardens are really Tradescantia x andersoniana; but RHS says its an invalid name and includes the hybrids under Tradescantia virginiana(one of the parents of the hybrids).