Chromosome numbers in Hieracium and Pilosella species (Asteraceae) from the Iberian Peninsula and the Balearic Islands

Mitotic chromosome numbers are reported from 16 Hieracium and two Pilosella species from the Iberian Peninsula and the Balearic Islands that are little known cytogenetically. The chromosome numbers of Hieracium aragonense Scheele ( 2n = 27, 36), H. compositum Lapeyr. ( 2n = 27), H. murcandidum G. Mateo ( 2n = 27), H. spathulatum Scheele ( 2n = 27), H. segurae Mateo ( 2n = 27), H. teruelanum Mateo ( 2n = 27), H. valentinum Pau ( 2n = 27), Pilosella pseudovahlii ( De Retz) Mateo ( 2n = 18), and P. tardans ( Peter) Sojak ( 2n = 36) were determined for the first time. New cytotypes were detected in H. cordifolium Lapeyr. ( 2n = 27) and H. loscosianum Scheele ( 2n = 36). The karyotype of the studied species was similar in overall morphology and comprised metacentric and submetacentric chromosomes; secondary constrictions ( up to two) were detected in the chromosome complements of some species. (c) 2007 The Linnean Society of London, Botanical Journal of the Linnean Society, 2007.