Systematics Section / ASPT
Vrijdaghs, Alexander , Goetghebeur, Paul , Smets, Erik , Muasya, A. Muthama .
An ontogenetic study of the lateral floral scales in Hellmuthia (Cyperaceae, Cyperoideae) and Paramapania (Cyperaceae, Mapanioideae).
IN 1976, Haines & Lye placed Hellmuthia in the Mapanioideae, among others because of the resemblance of two lateral scales (with ciliated keels) with the paired, ciliated basal scales in Mapanioid "flowers". Based on molecular phylogenetic analysis supported by pollen developmental evidence, Hellmuthia has eventually been placed in a Cyperoideae, tribe Cypereae, clade. In this study, we examined the floral ontogeny in Hellmuthia, comparing it with the floral ontogenetic pattern in other Cyperoideae and in Paramapania (Mapanioideae). The floral ontogeny in Hellmuthia occurs according to a typical Cyperoid pattern; the stamen primordia originate before the primordia of the perianth parts/gynoecium appear. Moreover, a third adaxially positioned floral scale has for the first time been observed. The positions and relative time of appearance of the floral scales in Hellmuthia make us conclude that they are perianth parts, hereby supporting the hypothesis based on cladistic analyses that Hellmuthia belongs to the Cyperoideae. The lateral scales in Paramapania, however, originate in a different sequence, which makes us decide that they are not homologous with the lateral scales in Hellmuthia.
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1 - K.U.Leuven, Laboratory of Plant Systematics, Instituut voor Plantkunde en Microbiologie, Kasteelpark Arenberg 31, Heverlee (LEUVEN), Belgium, B-3001
2 - Ghent University, Department of Biology, Research Group Spermatophytes, K.L.Ledeganckstraat 35, Gent, Belgium, B-9000
3 - National Herbarium of the Netherlands, Leiden University branch, P.O.Box 9514, Leiden, NL-2300 RA, Netherlands
4 - University of Cape Town, Department of Botany, Private Bag, Rondebosch, Western Cape, 7701, South Africa
Scanning electron microscopy (SEM).
Presentation Type: Poster:Posters for Sections
Location: Auditorium/Bell Memorial Union
Date: Tuesday, August 1st, 2006
Time: 12:30 PM