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Systematic and comparative anatomy of Cymbidieae (Orchidaceae)

2002; Oxford University Press; Volume: 139; Issue: 1 Linguagem: Inglês

10.1046/j.1095-8339.2002.00046.x

1095-8339

William Stern, Walter S. Judd,

Plant Diversity and Evolution

Cymbideae comprise an assemblage of 28 genera nearly all of which are represented in this study. Their anatomy is relatively homogenous with the exception of Govenia, in which roots lack velamen and pseudobulb vascular bundles lack sclerenchyma, conditions that do not obtain in other genera. Marginal fibre bundles in leaves of Grammatophyllum and Porphyroglottis consist of clusters of thicker-walled, narrower, epidermis-facing fibres as well as thinner-walled, wider, mesophyll-facing fibres. This feature also occurs in some species of Maxillaria. Baculate tilosomes appear in the roots of a majority of genera in Cymbidieae, as they do in species of Maxillaria, confirming DNA analyses showing a close relationship between tribes Cymbidieae and Maxillarieae. Govenia is singled out both on anatomical and molecular grounds as being ill-placed in Cymbidieae. Cladistic analysis produces only a few tentative hypotheses of phylogenetic relationships among the 28 genera, showing that anatomical characters are of limited value in assessing affinities within this tribe. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society, 2002, 139, 1–27.