Pollen morphology of some Achillea L. sect. Babounya (DC.) O. Hoffm. (Asteraceae) species from Turkey

The pollen morphology and exine structure of 52 specimens of the 14 species (15 taxa) of the genus Achillea L. section Babounya (DC.) O. Hoffm. (Asteraceae) distributed in Turkey were examined with light and scanning electron (SEM) microscopes. The pollen characteristics of 13 species (except for Achillea tenuifolia Lam.) are newly reported here. The pollen grains were oblate-spheroidal, prolate-spheroidal, subprolate and generally tricolporate, but sometimes tetracolporate, and even pentacolporate. The size of grains varied, ranged from 21.20 to 45 mu m on the polar axis mean, and from 18.10 to 43.14 mu m on the equatorial axis mean. The structure of the exine was doubletectate (Anthemoid pattern) and mean of exine thickness varied from 3.61 to 8.16 mu m. The sculpture was echinate both in light and SEM micrographs. Moreover, rugulate, microperforate and rugulate-microperforate ornamentations were observed in SEM. The results indicate that the examined species showed heterogeneity in pollen characteristics, both at an interspecies level and between specimens of a species collected from different localities. In addition, correlation between pollen size and chromosome number was discussed.