Pollen morphology of some species of Spermacoceae s.s. (Rubiaceae) of the Atlantic Forest, Rio de Janeiro, Brazil

• Published in: Acta botânica brasilica Vol. 34; no. 2; pp. 243 - 255
• Main Authors: Gonçalves-Esteves, Vania, Vieira, Gabrielle Reboredo Menezes, Carvalho, Renata Jacomo Paixão de, Crespo, Sonia Regina de Melo, Mendonça, Claudia Barbieri Ferreira
• Format: Journal Article
• Language: English
• Published: Sociedade Botânica do Brasil 01-06-2020
• Subjects: gentianales; multivariate analysis; palynology; rubioideae; systematics
• ISSN: 0102-3306; 1677-941X
• DOI: 10.1590/0102-33062019abb0286

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.