Karyological studies in Hieracium baeticum (Asteraceae) from the "Parque Natural de la Sierra de Grazalema" (Southern Spain)

Abstract

Hieracium baeticum is a triploid (2n = 27) species restricted to Iimestone mountains in Sand E Spain. 80th developing capitula and root tips from seedlings were used for the study. The karyotype suggests an allopolyploid ori gin of the taxon, and a relative close affinity between its parental is indicated by the possibility of partial pairing of most chromosomes during microsporogenesis. This process is completely disturbed starting from the first phases to degenerative pollen forrnation: none is forrned or shed. In more than 60 % of the f1owers, some kind of synapsis occurs in pollen mother cells, while there is total univalence in the rest. The species is considered strictly agamosperrnous in ali the studied populations.