ABSTRACT This work aimed to morphologically characterize 22 species of Spermacoceae s.s found in the Atlantic Forest in the state of Rio de Janeiro with the purpose of improving palynological knowledge of the studied species. The studied species included six species of Borreria and Denscantia cymosa, Emmeorhiza umbellata, Hexasepalum apiculatum, H. radula, H. teres, Manettia fimbriata, Mitracarpus eichleri, M. frigidus, M. hirtus, M. lhotzkyanus, M. megapotamicus, Oldenlandia salzmannii, Pentodon pentandrus, Richardia brasiliensis, Richardia scabra and Spermacoce rubescens. Acetolysed pollen grains were analyzed using light (LM) and scanning electron miscroscopy (SEM). The pollen grains varied in size (polar diameter) from medium to large, with the exception of Hexasepalum teres which was very large. Pollen grains were oblate spheroidal in most species, suboblate in six species, prolate spheroidal in Spermacoce rubescens and subprolate in Manettia fimbriata. All pollen grains were colporate, while number of apertures varied (three-19). The endoaperture was lolongate in most species and lalongate in four species. Sexine ornamentation varied among reticulate, reticulate-granulate, microreticulate, granulate with perforation, echinate-perforate and vermiculate. Pollen attributes were found to distinguish the studied species, but do not separate genera, confirming that Spermacoceae is euripolynic.

Resumo O objetivo desse estudo foi caracterizar a morfologia polínica das espécies de Grewioideae ocorrentes no estado do Rio de Janeiro. Grãos de pólen de 12 espécies foram examinados: tribo Apeibeae (Apeiba tibourbou, Corchorus hirsutus, Triumfetta althaeoides, T. grandiflora, T. obscura, T. rhomboidea) e tribo Grewieae (Luehea candicans, L. conwentzii, L. divaricata, L. grandiflora, L. ochrophylla, L. paniculata). Os grãos de pólen foram acetolisados, medidos, descritos e ilustrados sob microscopia de luz (ML). Para observar detalhes da superfície e abertura, grãos de pólen não acetolisados foram analisados em microscópio eletrônico de varredura (MEV) e, posteriormente, eletromicrografados. Foram caracterizados os grãos de pólen quanto à forma, ao tamanho, ao tipo de abertura, à polaridade e à constituição da exina. As espécies analisadas possuem grãos de pólen médios a grandes, isopolares, peroblatos a prolatos, 3-cólporos e sexina reticulada. Na chave polínica, a maioria das espécies pôde ser separada pelos atributos palinológicos. Isso permite considerar que as espécies aqui estudadas são euripolinícas, uma vez que é possível reconhecer a maioria das espécies pelas características palinológicas. Acredita-se que, o presente estudo fornece dados polínicos que podem auxiliar na identificação das espécies de Grewioideae que ocorrem no estado do Rio de Janeiro.

Abstract The objective of this study was to characterize the pollen morphology of the Grewioideae species occurring in the state of Rio de Janeiro. Pollen grains of 12 species were examined: tribe Apeibeae (Apeiba tibourbou, Corchorus hirsutus, Triumfetta althaeoides, T. grandiflora, T. obscura, T. rhomboidea) and tribe Grewieae (Luehea candicans, L. conwentzii, L. divaricata, L. grandiflora, L. ochrophylla, L. paniculata). The pollen grains were acetolysed, measured, described and illustrated under light microscopy (LM). To observe the surface and opening, pollen grains not acetolysed were analyzed in scanning electron microscope (SEM) and subsequently eletromicrographs. Were characterized pollen grains as the shape, size, opening type, the polarity and the exina constitution. The analyzed species have pollen grains medium to large, isopolar, peroblate to prolate, 3-colporate and reticulated sexine. In pollen key, most species could be separated those attributes palynological. It allows consider that species which were studied here are euripolinic, since it is possible to recognize most species by palynological characteristics. It is believed that the present study provides pollen characteristics data that may help identify the species of Grewioideae that occur in the State of Rio de Janeiro.