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Abstract Detail



Systematics Section/ASPT

Bauters, Kenneth [1], Asselman, Pieter [1], Goetghebeur, Paul [1], Larridon, Isabel [1].

Phylogenetics, ancestral state reconstruction, and a new infrageneric classification of Scleria (Cyperaceae) based on three DNA regions.

Scleria Bergius, commonly known as nut rushes or razor grasses, is with its ca. 250 representatives one of the major genera in the sedge family (Cyperaceae). Within Cyperaceae, the genus is placed in the monotypic tribe Sclerieae. Scleria has a pantropical distribution, locally extending into (warm) temperate regions. Approximately 113 species are known from the Americas, circa 96 from Africa and about 59 from Asia and Oceania. Previously, numerous infrageneric classifications were proposed based solely on morphological data, and most of them only treated species from defined geographical regions. In this study, DNA from 101 Scleria species from the entire distribution range of the genus were extracted and amplified for three markers: the coding chloroplast marker ndhF, the chloroplast intron rps16 and the nuclear region ITS. A molecular phylogenetic hypothesis was constructed using Bayesian and maximum likelihood approaches. Additionally, four morphological characters were used to reconstruct ancestral states at important nodes using the program BayesTraits. Results confirm Scleria to be monophyletic as a sister group of the tribe Bisboeckelereae. Furthermore, a subdivision of Scleria into four subgenera (subg. Browniea, subg. Hypoporum, subg. Scirposcleria and subg. Scleria) was recovered. Subgenus Scleria can be further divided into nine monophyletic sections, all easily recognised by their morphology. Ancestral state reconstruction showed an ancestral position for androgynous spikelets, a trilobed hypogynium and a subcapitate inflorescence. Androgynous spikelets are found in the three basal subgenera while in subgenus Scleria an evolutionary trend towards subandrogynous and strictly unisexual spikelets is noted. Hypogynia are generally well developed with the exception of subg. Hypoporum. Here, the hypogynium is reduced or lost. Inflorescences in Scleria vary from densely paniculate to subcapitate, only in subg. Hypoporum a glomerate-spicate inflorescence is found. The pseudopremorse leaf habit arose only once, within subg. Scleria. In this section, one reversal to the normal leaf tip is also present. A new infrageneric classification based on monophyletic species groups, and supported by morphology is suggested.


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1 - Ghent University, Biology Department, K.L. Ledeganckstraat 35, Gent, 9000, Belgium

Keywords:
Cyperaceae
Scleria
ancestral states reconstruction
hypogynium
rps16
ndhF
ITS
systematics.

Presentation Type: Poster:Posters for Sections
Session: P
Location: Hall D/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 5:30 PM
Number: PSY014
Abstract ID:260
Candidate for Awards:None


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