PERICARP ANATOMY AND EVOLUTION IN CORIARIA (CORIARIACEAE)

The first overall study of pericarp anatomy of Coriaria is presented to discuss its evolution and relationships within a genus. All 14 species investigated (including 11 narrowly defined species) have somewhat bilaterally flattened mature fruits with five to seven (or more) longitudinal costae. They share a usually nine-(or more-)cell-layered (at intercostal region), stratified mature pericarp, which is basically constructed by an exocarp, an outer, a middle and an inner zone of mesocarp, and an endocarp. While a multi-layered endocarp is composed of circumferentially elongate fibres, a multi-layered inner zone of the mesocarp comprises longitudinally elongate fibres. Despite its uncertain systematic value, the presence of those fibres arranged crisscross is a characteristic feature of the genus. Comparisons among species indicate that Coriaria terminalis, a species of the Eastern Hemisphere, retains a basic or archaic, well-stratified pericarp structure similar to the one found in all the species investigated of the Southern and Western Hemisphere, and that four species of Asia, Coriaria napalensis, C. sinica, C. intermedia and C. japonica, share a specialized structure (lacking the outer zone of the mesocarp) indicative of their mutual close affinity. Comparisons further suggest distinctness of Coriaria intermedia, as well as variously derived position of e. myrtifolia and C. japonica.