Hernández-Hernández T., Hernández H. M., De-Nova J. A., Puente R., Eguiarte L. E., Magallón S., Phylogenetic relationships and evolution of growth form in Cactaceae, American Journal of Botany, 2011, 98(1):44-61, doi: 10.3732/ajb.1000129
The molecular analysis presents cactus relationships and growth form evolution. Reconstruction indicates repeated origins of similar forms in different lineages.