Palynological Study of Tribe Anthemideae (Asteraceae) in Iran

The pollen grains of 32 populations from 13 genera belonging to the tribe Anthemideae-Asteraceae (one to three populations of each species) from Iran were studied by light and scanning electron microscopes. Pollen grains of all the studied samples were tricolporate. Based on pollen shape, 55, 22, 15 and 8 % were oblate-spheroidal, suboblate, spheroidal and prolate-spheroidal, respectively. The pollen grains with oblate-spheroidal and spheroidal shapes were common among the genera studied. The pollen grains of all taxa were operculate and tricolporate. The pollen ornamentations were echinate perforate except Artemisia that was spinulose non-perforate in SEM. The dendrogram obtained from UPGMA method based on four quantitative and qualitative characters was classified into two main clusters. The first cluster (A) includes populations of Artemisia which show "Artemisia-type" pollen, while the second cluster (B) comprises of the rest of the taxa which have pollen grains of "Anthemis- type". The subcluster B-1 possesses samples with bigger (polar axis 28.64–32.5 µm and equatorial axis 30.65–33.2 µm) pollen grains and subcluster B-2 comprised of populations with smaller (polar axis 21.69-30.38 µm and equatorial axis 23.29–32.4 µm) pollen grains. The results showed that pollen micromorphological characters could be utilized in interpretation of intergeneric relationship of tribe Anthemideae. Moreover, pollen size and shape were determined as taxonomic diagnostic characteristics.