Wood Anatomy of Papaveraceae, with Comments on Vessel Restriction Patterns

Abstract

Qualitative and quantitative features are reported for Bocconia, Dendromecon, Dicentra, Hunnemannia, and Romneya. Bocconia differs from the other genera by its wide vessels, few per group, and few per mm2; it shows paedomorphosis in vessel element length and ray histology. In respects other than these, it agrees with features common to woody Papaveraceae; these features in turn occur in families of Papaverales (Berberidaceae, Lardizabalaceae, Ranunculaceae): vessels in diagonal groups; presence of both libriform fibres and vasicentric tracheids; nucleated nature of libriform fibres; rays almost exclusively multiseriate; rays wide, tall, and composed mostly of procumbent cells; wood storied to various degrees. Additional features show resemblance between one or more genera of Papaveraceae and other families of Papaverales. Bocconia is distinctive among Papaveraceae in its relatively mesomorphic wood, which may in part be explainable on the basis of stern succulence. The occurrence of avessei restriction pattern - vessels in the centre of fascicular areas (axial portions of secondary xylem between rays) not in contact with rays - in Dicentra and Hunnemannia is like that of other genera of Papaverales such as Nandina. An explanation for the significance of vessel restriction, involving genera other than those of Papaverales (Launea, Valeriana), is attempted.