Pollen morphology of some species of Calliandra Benth. (Leguminosae ‐ Mimosoideae) from Bahia, Brazil

Abstract

A study of pollen morphology, in species of the genus Calliandra (Leguminosae ‐ Mimosoideae) which occur in the Chapada Diamantina, Bahia, Brazil, is presented. The pollen was examined using light (LM) and scanning electron microscopy (SEM). Samples were prepared by the acetolysis method; the pollen units were measured and photographed. All 21 species studied have polyads comprising eight pollen grains. The polyads conform to one or other of two basic types: either with an exinous appendiculate apical pollen grain or, with a more or less acute apical pollen grain but without an exinous appendix. Species from sections Androcallis (C. bella, C. depauperata, C. harrisii, C. macrocalyx, C. sessilis and C. spinosa) and Microcallis (C. leptopoda) are included in the non‐appendiculate polyad group, while the remaining species, with appendiculate polyads, are included in the section Calliandra (C. asplenioides, C. bahiana var. bahiana, C. coccinea, C. elegans, C. ganevii, C. germana, C. hirsuticaulis, C. hirtiflora var. ripicola, C. hygrophila, C. lanata, C. lintea, C. semisepulta, C. stelligera and C. viscidula). In all the species the individual pollen grains within the polyad are porate, and in many of these the pori are annulate. The pattern of sexine ornamentation, although variable, is basically rugulate when observed with SEM. Some of the polyad characters have proved useful in the corroboration of previous infrageneric classifications of the genus.