Stem and nodal anatomy of Antigonon, Brunnichia, Coccoloba, Muehlenbeckia, and Podopterus was investigated. These genera have historically been united within the tribe Coccolobeae. Seventeen anatomical features were compared among 19 species. Two groups of character states were identified as significant. First, the width of the band of sclerenchyma fibers correlates with the presence of an endodermoid layer. Second, two patterns of leaf trace divergence are present. Species either have traces that diverge simultaneously or have the main trace diverge initially followed by the lateral traces. Furthermore, the lateral leaf trace pathway is either perpendicular to the stem and the traces fuse together before entering the petiole or the trace pathway is parallel to the stem and the traces enter the petiole independently. The patterns of leaf trace divergence and the pathway of traces to the petiole are stable at the generic level.

Key words: anatomy, Coccolobeae, node, Polygonaceae, stem, systematics.