FREID, ETHAN. Department of Botany, Miami University, Oxford, OH 45056. - Stem and nodal anatomy of the tribe Coccolobeae (Polygonaceae).
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.