Pericarp structure and phylogeny of Lamiaceae subfamily Pogostemonoideae

The pericarp structure has been investigated in 11 species representing the genera of the subfamily Pogostemonoideae (emend. Cantino et al. 1992): Anisomeles, Colebrookea, Comanthosphace, Leucosceptrum, Pogostemon and Rostrinucula . The pericarp structure of Anisomeles, Colebrookea and Pogostemon have been found to resemble that of the subfamilies Lamioideae or Nepetoideae. The three related genera, Comanthosphace, Leucosceptrum and Rostrinucula have been found to have a divergent type of pericarp, which lacks sclerenchyma and has druses and a type of cells with scalariform secondary thickenings in the mesocarp. The three genera are suggested to be extraneous in Pogostemonoideae and their systematic position is uncertain.