Jäger-Zürn, I. 2009. WHAT IS THE DITHECOUS LEAF? AN INVESTIGATION OF THE NEOTROPICAL PODOSTEMUM RUTIFOLIUM SUBSP. RICCIIFORME (PODOSTEMACEAE – PODOSTEMOIDEAE). Edinburgh Journal of Botany. 66, 3 (Oct. 2009), 469–481. DOI:https://doi.org/10.1017/S0960428609990114.