IngentaConnect The Systematic Value of Morphological Characters in Senecio sect....

Authors: Pelser, Pieter B.; van den Hof, Kevin; Gravendeel, Barbara; van der Meijden, Ruud

Source: Systematic Botany, Volume 29, Number 3, 1 July 2004 , pp. 790-805(16)

Publisher: American Society of Plant Taxonomists

Abstract:

The systematic value of morphological characters in Senecio sect. Jacobaea (Asteraceae) is studied using separate and combined parsimony analyses of morphological and DNA sequence data. These analyses are the first studies of morphological characters in a phylogenetic context in Senecio. Although the morphological data set forms a valuable addition to DNA sequences in providing greater resolution and support for several molecular-based clades, most characters are not suitable for identifying clades containing more than just a few closely related species. One of these characters, the stigmatic configuration, commonly used to study generic and subtribal limits of Senecioneae, is too variable for classification purposes in sect. Jacobaea. Among the four morphological characters that can be used to identify relatively large clades in the section are two indumentum characters. Because indumentum characters also have been found to be phylogenetically informative in other sections and genera in Senecioneae, we argue that they might be suitable for classification purposes throughout this tribe. We show that on the basis of these and other morphological characters and DNA sequences, S. gallerandianus and S. maroccanus should be included in sect. Jacobaea. This brings the total number of species in this section to 26.

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The Systematic Value of Morphological Characters in Senecio sect. Jacobaea (Asteraceae) as Compared to DNA Sequences