Palynological Features as a Systematic Marker in Artemisia L. and Related Genera (Asteraceae, Anthemideae) - II: Implications for Subtribe Artemisiinae Delimitation

Abstract: Using optical and scanning electron microscopy, we completed a palynological study of the subtribe Artemisiinae (Asteraceae, Anthemideae), which we started in a previous paper. This subtribe contains different genera with a systematic position that, in many cases, has been controversial. There is a group of genera closely related to Artemisia, and another one more related to Chrysanthemum sensu lato. We confirm the existence of two pollen morphological patterns - concerning exine ornamentation - in the tribe Anthemideae and in the subtribe Artemisiinae as currently considered: one with long spines ( Anthemis type) and the other with short spinules ( Artemisia type). This feature is a good taxonomic marker, well correlated with other morphological and with molecular characters. This enables a new delimitation of the subtribe Artemisiinae, which is characterized by pollen grain ornamentation constituted by short spinules (microechinate pollen), and should be restricted to Artemisia and the closely related genera that share this trait.