Salazar GA, Cabrera LI, Madrinan S, Chase MW (2009) Phylogenetic relationships of Cranichidinae and Prescottiinae (Orchidaceae, Cranichideae) inferred from plastid and nuclear DNA sequences. Annals of Botany 104: 403-416. doi: 10.1093/aob/mcn257.
There is no corrections for Ponthieva fertilis yet.