| Abstract Detail
Developmental and Structural Section Gonzalez, Favio [1], Rudall, Paula, J. [2]. Floral morphology of the neotropical family Metteniusaceae, an isolated member of the lamiids. A recent phylogenetic analysis indicated that the small neotropical Metteniusaceae is an isolated member of lamiids (euasterids I), as sister either to the equally enigmatic New Caledonian Oncothecaceae or to the (Boraginaceae + Gentianales + Lamiales + Solanales + Vahliaceae) clade. In this context, floral development was investigated in order to assess the systematic and evolutionary significance of two of the diagnostic traits of Metteniusa, the moniliform anthers and the unilocular gynoecium. Flowers of Metteniusaceae are pentamerous, the tubular corolla develops by late sympetaly, the stamens have a row of up to 16 sporangia per pollen sac, which open by four stomia. The gynoecium is monosymmetric and contains two pendent ovules with a massive, vascularized integument. A monosymmetric gynoecium indicates ´pseudomonomery´, a developmental process that is widespread in members of at least 40 angiosperm families; this process involves initiation of two or more carpel primordia, of which only one completely develops. Comparison with other ´pseudomonomerous´ taxa, both in lamiids and other angiosperms, leads us to propose four types of pseudomonomery. The unitegmic ovules and late sympetaly of Metteniusa agree with its placement in the lamiids. The polysporangiate stamens, monosymmetric gynoecium, and vascularized integument are proposed here as autapomorphic in Metteniusaceae and support its recognition as a distinct family. The pentacarpellary gynoecium (together with pentalacunar nodes) is consistent to the hypothesis of Metteniusaceae and Oncothecaceae as sister taxa.
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1 - National University of Colombia, Institute of Natural Sciences, Ap Ae 7495, Bogota, D.C., 01, Colombia
2 - Royal Botanic Gardens, Kew, Jodrell Laboratory, Richmond, Surrey, TW9 3AB, United Kingdom
Keywords:
Floral development
floral morphology
Lamiids
Metteniusa
Metteniusaceae
Oncothecaceae
Polysporangiate anthers
Pseudomonomery.
Presentation Type: Oral Paper:Papers for Sections
Session: CP26
Location: Boulevard C/Hilton
Date: Tuesday, July 10th, 2007
Time: 11:30 AM
Number: CP26013
Abstract ID:1022 |
