Diversity of Nodal Structure in Mallotus nudiflorus (L.) Kulju & Welzen (Euphorbiaceae) – insight into the evolution of "Howard's Split-Lateral"

In 1970, Howard proposed a fifth type of nodal anatomy pattern, where a single vascular trace from the stele is associated with more than one leaf and termed it as “split-lateral”. Several workers observed this type of nodal vascular trace in different angiosperm families, but with rather conflicting interpretations. The present study added another family – Euphorbiaceae – in the list of such nodal type and, based on the observation of different nodal configurations of the species Mallotus nudiflorus (L.) Kulju & Welzen (basionym Trewia nudiflora L.), the evolutionary consequences of “split-lateral” were discussed.