Vascular systems in the magnoliaceae

Abstract

The vascular anatomy of seven genera of Magnoliaceae:Elmerrillia, Liriodendron, Magnolia, Manglietia, Michelia, Paramichelia andTalauma, was examined. Based on the primary vascular bundles, and not on the protoxylem courses, the vasculature was reconstructed. The vasculature was observed ontogenetically throughout the axes in both the flowers and vegetative shoots to determine the fundamental plan of the vascular systems, including the cortical and outer cortical vascular systems in the flowers. Each cortical strand, which was previously treated as a single strand, was found to consist of several collateral bundles arranged concentrically. The central, cortical and outer cortical vascular systems in the flowers are homologous and show parastichous patterns. The primary vascular system in the vegetative shoots is likewise arranged in a parastichous pattern, although it was previously considered to have a non-parastichous pattern.The fundamental plan of the vascular system in the Magnoliaceae is always consistent in having no relation to the size of flowers.