Pollen morphology of the subfamily Barnadesioideae (Asteraceae) and its phylogenetic and taxonomic significance

The pollen morphology of 59 species of the genera Arnaldoa, Barnadesia, Chu quiraga, Dasyphyllum, Doniophyton, Duseniella, Fulcaldea, Huarpea and Schle chtendalia belonging to the Barnadesioideae has been studied with light and scanning electron microscopy. Three main pollen types were recognized: (1) lophate pollen found in Barnadesia and Huarpea; (2) pollen with intercolpa l depressions in Arnaldoa and some species of Dasyphyllum (subtypes I, II a nd III) and Schlechtendalia; and (3) pollen without depressions found in Ch uquiraga, Dasyphyllum p.p., Doniophyton, Duseniella and Fulcaldea. In Dasyp hyllum cryptocephalum and D. tricophyllum, we recognized a new type with 21 -23 depressions. A key for the identification of pollen types is presented. Phylogenetic significance of the three palynological characters (morpholog y, sculpture and structure) is interpreted through phylogenies of Barnadesi oideae proposed by earlier workers. Cladograms show the monophyletic group Barnadesia-Huarpea supported by a smooth exine and lophate pollen. Our resu lts show that the 1-layered exine represents a synapomorphy for Dasyphyllum , Arnaldoa, Fulcaldea, Barnadesia and the Huarpea group. (C) 1998 Elsevier Science B.V. All rights reserved.