The palynotaxonomic study of Cheiloclinium Miers was conducted in order to contribute to a better characterization of this genus, represented in Latin-America by 20 species. Pollen grains from 38 specimens representing 14 Brazilian species were examined. The pollen material was acetolyzed, measured, described and illustrated using ligth and scanning electron microscopy (SEM). The data obtained were statistically analysed. The pollen grains of Cheiloclinium are small in size (medium size only in C. pedunculatum A.C. Sm.), isopolar, suboblate, oblate-spheroidal or subprolate, amb subtriangular or triangular, polar area small or very small (only in C. pedunculatum and C. podostemmum (Sandw.) A.C. Sm.), 3-colporate with lalongate endoaperture (circular only in C. diffusiflorum (Miers) A.C. Sm.) and microreticulate, reticulate or granulate. Cheiloclinium is a stenopalynous genus. However it was possible to elaborate a pollen type key based upon light microscope observations and to distinguish between Cheiloclinium species or species group showing that the pollen characteristics are useful for the taxonomic study of this genus. Pollen grains of Cheiloclinium were never analized before.
Pollen morphology; Cheiloclinium; Hippocrateaceae
