The pollen morphology and exine structure of 10 Mentha L. species were investigated using light microscopy and scanning electron microscopy. The pollen grains of all 11 species were hexazonocolpate with granular membranes and a circular amb, varying in shape from prolate-spheroidal to suboblate. Different colpus shapes were recognized in M. x dumetorum. The exine was bireticulate in section Pulegium, and reticulate in section Menthae. A correlation was found between pollen size and chromosome number. The results indicate that the pollen characters of the genus Mentha are valuable for taxonomic applications and may be useful for classification. (c) 2008 Uludag University. Journal compilation (c) 2008 The Linnean Society of London.