ORIGINAL ARTICLE Pollen morphology in tribe Dicomeae Panero and Funk (Asteraceae) A. Pereira Coutinho • R. Almeida da Silva • D. Sa ´ da Bandeira • S. Ortiz Received: 27 January 2012 / Accepted: 16 July 2012 / Published online: 17 August 2012 Ó Springer-Verlag 2012 Abstract To better understand the taxonomy and phy- logeny of the Dicomeae (Asteraceae) the pollen morphol- ogy of seven genera including 15 species of that tribe and six genera with seven species belonging to five related tribes was studied by use of light and scanning electron microscopy. The quantitative data were analysed by use of principal-components analysis (PCA). The exine ultra- structure of Erythrocephalum longifolium and Pleiotaxis rugosa was also studied by use of transmission electron microscopy. Three pollen types were distinguishable from the apertural, columellar, and spinular morphology and inter-spinular sculpture. A dichotomous key to these pollen types is proposed. The existence of the Dicomeae as an independent tribe and its subdivision in two subtribes (Dicominae and Pleiotaxinae) are supported by this study, which also suggests the Oldenburgieae and the Tarcho- nantheae are the closest tribes to Dicomeae. Keywords Dicomeae Á Pollen morphology Á Asteraceae Á Taxonomy Introduction The tribe Dicomeae was firstly described by Panero and Funk (2002), and includes eight genera and 95 species of perennial herbs, shrubs, or small trees, mainly with an African and Malagasy distribution, though one species occurs in the Arabian Peninsula and another in India and Pakistan (Ortiz 2000; Ortiz et al. 2009). This taxon com- prises most of the African genera previously included in the Mutisieae by authors such as Hoffmann (1890), Jeffrey (1967), Cabrera (1977) and Bremer (1994). Morphological phylogenetic analysis by Ortiz (2000), ITS (rDNA) and ndhF (cpDNA) analysis by Ortiz et al. (2009), and ndhF? trnL-F (cpDNA) analysis by Ortiz et al. (unpublished) revealed that the genera Cloiselia, Dicoma, ‘‘Dicomopsis’’ (unpublished), Macledium, and Pasa- ccardoa belong to a monophyletic group (Dicoma s. l.) and seem closely related to each other. The other three genera (Erythrocephalum, Gladiopappus, and Pleiotaxis) are quite dissimilar from the taxa of that clade. No sequence data of Gladiopappus are yet available but Erythrocephalum and Pleiotaxis constitute a separate monophyletic group and a distinct subtribe (Pleiotaxinae—Ortiz et al. unpublished) or even a new tribe of Asteraceae (Ortiz et al. 2009). According to Ortiz et al. (unpublished), the other genera of Dicomeae belong to subtribe Dicominae. According to many authors (Skvarla and Larson 1965; Skvarla et al. 1977, 2005; Bolick 1978, 1991; Zavada and De Villiers 2000; Tellerı ´a and Katinas 2005; Pereira Coutinho and Dinis 2007; Wortley et al. 2008) a knowledge of pollen morphology is important to understanding the taxonomy, phylogeny, and ecology of the Asteraceae. For this reason we investigated, by use of light and scanning electron micro- scopy, pollen morphology in seven genera (Cloiselia, Dicoma, ‘‘Dicomopsis’’, Erythrocephalum, Macledium, A. Pereira Coutinho (&) Á D. Sa ´ da Bandeira Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, Coimbra, Portugal e-mail: cafe@bot.uc.pt R. Almeida da Silva Department of Biology and CIBIO, Faculty of Sciences, University of Porto, Porto, Portugal S. Ortiz Department of Botany, Faculty of Pharmacy, University of Santiago de Compostela, Santiago de Compostela, Spain 123 Plant Syst Evol (2012) 298:1851–1865 DOI 10.1007/s00606-012-0686-5