Pollen morphology of some species of the Family Asteraceae from the Alpine Zone, Deosai Plateau, northern Pakistan

The pollen morphology, with special reference to exine sculpture, of some species of the Family Asteraceae from the Deosai Plateau of northern Pakistan has been analysed. Scanning electron microscopy of high-altitude Himalayan pollen taxa has been attempted for the first time. The pollen are all tricolporate and echinate. The exine sculpture is echinolophate (fenestrate) in Taraxacum tibetanum. The spines are reduced in two species of Artemisia and in Tanacetum gracile. By contrast, spine development exhibits greater diversity in the reminder of the species. The exine sculpture and spine morphology are important for the differentiation of species. Pollen fertility ranges from 82% to 94%, which indicates that the selected plant species are well established in the Alpine Zone.