What is "dialypetalum"

Dialypetalum is a genus of plants endemic to Madagascar. It differs from other Lobelioideae in having regular ( actinomorphic) flowers with virtually free petals, and in being dioecious. It contains the following species, accepted as of July 2014:..

1. Dialypetalum compactum Zahlbr.
2. Dialypetalum floribundum Benth. in G.Bentham & J.D.Hooker
3. Dialypetalum humbertianum E.Wimm. in H.G.A.Engler
4. Dialypetalum × hybridum E.Wimm. in H.G.A.Engler (D. compactum × D. floribundum)
5. Dialypetalum montanum E.Wimm. in H.G.A.Engler
6. Dialypetalum stenopetalum E.Wimm. in H.G.A.Engler