ABSTRACT
(Palynotaxonomy of the species of the Acacia (Leguminosae-Mimosoideae) from the Brasilian semi-arid region) The pollen of 12 species of Acacia: A. farnesiana (L.) Willd. (Acacia subg. Acacia) e A. bahiensis Benth., A. globosa A. Bocage & S. Miotto, A. kallunkiae Grimes & Barneby, A. langsdorffii Benth., A. martiusiana (Steud.) Burkart, A. monacantha DC., A. piauhiensis Benth., A. polyphylla DC., A. riparia Kunth, A. tenuifolia (L.) Willd., and A. velutina DC. (Acacia subg. Aculeiferum) was studied. Material was acetolized, measured, described and illustrated using light and scanning electron microscopy. The pollen grains in Acacia are bound in medium or large calimad polyads, spheroidal in shape on frontal view and elliptical from the side, containing 16 pollen grains, organized regularly with 8 pollen grains on each side. Pollen grains are 4-porate. In A. farnesiana, 24-32 pollen grains are found irregularly organized, while pollen grains are 3-sulcate. The polyad pollen grains are small, subsquared on distal view and pyramidal on the equatorial view, sexine is thicker than the nexine. Species could not be separated by their palynological features, except for A. farnesiana.
Key words:
palynology; semi-arid; caatinga; Mimosaceae; Fabaceae