POLLEN WALL ULTRASTRUCTURES OF THE SUBTRIBE TUSSILAGININAE (ASTERACEAE: SENECIONEAE) OF THE EASTERN ASIA AND THEIR SYSTEMATIC AND TAXONOMIC SIGNIFICANCE

The pollen wall ultrastructures of 15 species, representing 11 genera in the Subtribe Tussilagininae and related taxa of Trib.Senecioneae (Asteraceae) from China were investigated under TEM.There are two types of pollen wall ultrastructure:“Helianthoid” and “Senecioid”.The “Helianthoid” type was detected in Doronicum, Farfugium and Nannoglottis while the “Senecioid” was found in the remained genera.Based mainly on the present investigation and combined with the other evidence, it is suggested that Farfugium should not be related to the Ligularia, and Nannoglottis should be near to the Astereae.