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Comparative Studies of the Nodal and Vascular Anatomy in the Neotropical Cyatheaceae. I. Metaxya and Lophosoria
Terry W. Lucansky
American Journal of Botany
Vol. 61, No. 5 (May - Jun., 1974), pp. 464-471
Published by: Botanical Society of America, Inc.
Stable URL: http://www.jstor.org/stable/2442017
Page Count: 8
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Comparative studies of the nodal and vascular anatomy in the monotypic genera Metaxya and Lophosoria are discussed as they relate to the taxonomy and phylogeny of the Cyatheaceae. Both genera are distinctive and primitive with respect to habit, stem and petiole indument, stelar pattern, and nodal anatomy. Metaxya possesses a prostrate, dorsiventral rhizome, whereas a short, upright radial stem occurs in Lophosoria. Trichomes occur on the stems and leaf petioles of these genera. Both Metaxya and Lophosoria have a spiral phyllotaxy, and adventitious buds occur on the petiole bases. The stelar pattern is basically a siphonostele, although frequently a dictyostele is found in Lophosoria. Accessory bundles are lacking in both genera. A characteristic petiole pattern is found in these genera, with an increase in complexity from an undivided strand in Metaxya to the three-parted petiole pattern in Lophosoria. Data from nodal and vascular anatomy indicate that these taxa are distinct from the other genera in the Cyatheaceae and belong in an independent position at the base of the Cyatheoid line, although in some respects an affinity to members of the Dicksoniaceae is indicated.
American Journal of Botany © 1974 Botanical Society of America, Inc.