188 FLORA (2003) 198 Flora (2003) 198, 188–199 http://www.urbanfischer.de/journals/flora Floral anatomy of Eriocaulon elichrysoides and Syngonanthus caulescens (Eriocaulaceae) Michele Marcelino Rosa* & Vera Lucia Scatena Departamento de Botânica, Instituto de Biociências, Universidade Estadual Paulista, São Paulo, Brasil Submitted: Oct 7, 2002 · Accepted: Nov 28, 2002 Summary The floral anatomy of Eriocaulon elichrysoides Bong. and Syngonanthus caulescens (Poir.) Ruhland, from Brazilian mountain rock savannas (campos rupestres) was studied. The staminate flowers of E. elichrysoides present a diplostemonous androecium with six stamens, and those of S. caulescens present an isostemonous androecium with three stamens and three scalelike staminodes. Eriocaulon elichrysoides and S. caulescens have three nectariferous pistillodes located in the central portion of the receptacle. The pistillate flowers of E. elichrysoides present three simple styles while those of S. caulescens present three simple styles interspersed with three nectariferous appendices. Both the styles of E. elichrysoides and the nectariferous appendices of S. caulescens are vascularized by the dorsal vascular bundles of the carpels. The styles of S. caulescens lack vascularization. At the base of the gynoecium of E. elichrysoides there are six staminodes and there are three in the S. caulescens. Entomophily is suggested as the pollination syndrome in E. elichrysoides and S. caulescens as they present staminate and pistillate flowers with nectariferous structures. The ancestral character in Eriocaulon is probably given by the presence of the two staminal whorls. The staminate flowers of S. caulescens are probably derived from the reduction of a diplostemonous ancestral androecium. It remains open whether the pistillate flowers with nectariferous appendices present an ancestral character or a derived one. Key words : Eriocaulaceae, floral anatomy, Eriocaulon elichrysoides, Syngonanthus caulescens, monocots, pollination biology Introduction The family Eriocaulaceae includes about 1 200 species assembled in 10 genera with a pantropical distribution. The representatives of the family are frequent compo- nents of mountainous vegetation and grow mainly in sandy and swampy soils. The largest concentration of the species occurs in South America, especially in the mountain rock savannas (campos rupestres) of Minas Gerais and Bahia (Brazil) and on the table mountains (tepuis) of South Venezuela (Giulietti et al. 1995). The only world monograph of the family was done by Ruhland (1903) who established the systematic basis for the family which is still in use. He recognized two subfamilies and nine genera : Eriocaulon L. and Mesanthemum Koern. (Eriocauloideae) ; Blastocaulon Ruhland, Lachnocaulon Kunth., Leiothrix Ruhland, Paepalanthus Mart., Philodice Mart., Syngonanthus Ruhland and Tonina Aubl. (Paepalanthoideae). Since then, new genera have been proposed and synonymized and among these, only Rondonanthus (Herzog 1931) is still accepted. Another classsification was proposed by Stützel (1985) who distinguished three subfamilies : Eriocau- loideae (Eriocaulon) ; Paepalanthoideae (Blastocaulon, Lachnocaulon, Leiothrix, Paepalanthus, Rondonan- thus, Tonina) ; Syngonanthoideae (Mesanthemum, Phi- lodice, Syngonanthus, Wurdackia). Wurdackia was recently synonymized in Rondonanthus (Hensold & Giulietti 1991). In a recent summary on affinities and relationships within the family, Stützel (1998) abandoned the con- cept which was based on the assumption that Eriocau- lon was the most primitive genus within the family. He 0367-2530/03/198/03-199 $ 15.00/0 * Corresponding author : Michele Marcelino Rosa, Departamento de Botânica, Instituto de Biociências, Universidade Esta- dual Paulista, C.P. 199, Rio Claro – São Paulo, 13506-900, Brasil, e-mail: mm_rosa@hotmail.com