Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 2 of 2
Full-Text Articles in Life Sciences
Tracheid Dimorphism: A New Pathway In Evolution Of Imperforate Tracheary Elements, Sherwin Carlquist
Tracheid Dimorphism: A New Pathway In Evolution Of Imperforate Tracheary Elements, Sherwin Carlquist
Aliso: A Journal of Systematic and Floristic Botany
Certain dicotyledon families characteristically have tracheids as their imperforate tracheary element type. Of these, six families are anomalous by having septate (or nonseptate but living) fiber-tracheids or libriform fibers coexisting with the tracheids in some species or genera (Austrobaileyaceae, Celastraceae, Convolvulaceae, Ericaceae, and Grossulariaceae, and Rosaceae). Data from the literature and original data on wood anatomy of these families are presented. A theory of tracheid dimorphism is developed to account for these instances of tracheids combined with fiber-tracheids or libriform fibers. According to this theory, septate or living fiber-tracheids or libriform fibers are produced in addition to tracheids, starting with …
Rosaceous Chamaebatiaria-Like Foliage From The Paleogene Of Western North America, Jack A. Wolfe, Wesley Wehr
Rosaceous Chamaebatiaria-Like Foliage From The Paleogene Of Western North America, Jack A. Wolfe, Wesley Wehr
Aliso: A Journal of Systematic and Floristic Botany
Chamaebatiaria and Chamaebatia, two characteristic genera of the Californian floristic province, are traditionally placed in different subfamilies of Rosaceae , Spiraeoideae and Rosoideae, respectively. Analysis of the foliar and reproductive characters of the extant species of these genera indicates that the two genera could be closely related and the assignment of Chamaebatia to Rosoideae invalid. Fossil leaves of lineages of both genera occur in the Paleogene montane floras of the Rocky Mountain region and provide evidence that the two lineages diverged from a common ancestor in the Eocene. The common ancestor probably was adapted to sunny habitats in mesic coniferous …