STEVENSON, DENNIS W.* AND ANDREW W. DOUGLAS. New York Botanical Gardens, Bronx, NY 10458, and, Botany Department, The Field Museum, Roosevelt Rd at Lake Shore Drive, Chicago, IL 60605. - Hülles, ocreas and metamers: vegetative architecture of Platanus revisited.
Multiple molecular data based phylogenies support a relationship among
Platanaceae, Nelumbonaceae, and Proteaceae. Developmental and
anatomical results are interpreted in a metameric framework to clarify
the organizational architecture of Platanus. These studies clarify
the organization of different leaves/pherophylls (hülle), ocreas and
the development of axillary meristems in intrapetiolar positions.
Based on metameric concepts, the platanoid architecture is composed of
a conserved repeating growth unit (RGU) composed of six - eight
metamers. Each RGU generally terminates with the production of an
inflorescence. There is variation among the metamers of an RGU
depending on their position along the axis. Integrated into a
phylogenetic comparative framework, these data provide a better
understanding regarding the architectural transformations associated
with Platanus and its putative relatives.
Key words: hulle, ocreas, phylogenetics, Platanaceae, vegetative architecture