Previous analyses of Asteropeia and Physena have not compared the wood anatomy of these genera to those of Caryophyllales s.l. Molecular evidence shows that the two genera form a clade that is a sister group of the core Caryophyllales. Synapomorphies of the Asteropeia—Physena clade include small circular alternate pits on vessels, presence of vasicentric tracheids plus fiber-tracheids, presence of abaxial-confluent plus diffuse axial parenchyma, and presence of predominantly uniseriate rays. These features are analyzed with respect to habit and ecology of the two genera. Solitary vessels, present in both genera, are related to the presence of vasicentric tracheids. Autapomorphies in the two genera seem related to adaptations by Physena as a shrub of moderately dry habitats (e.g., narrower vessel elements, abundant vasicentric tracheids, square to erect cells in rays) as compared to alternate character expressions that seem related to the arboreal habit and humid forest ecology of Asteropeia. The functional significance of vasicentric tracheids and fiber-tracheids in dicotyledons is briefly reviewed in the light of wood anatomy of the two genera.