A karyological analysis of some taxa of Genista sect. Spartioides, distributed in the Western part of the Mediterranean region, was carried out. In the Genista cinerea group, G. majorica and G. cinerea ssp. cinerea have the chromosome number 2n = 48+(0-2B), while a population of G. cinerascens from Portugal has the new numbers with higher degrees of ploidy 2n = 72+(0-SB), rarely 2n = 96+(0-2B). G.florida s.l., like ssp. florida and ssp. polygaliphylla, have 2n = 48+(0-3B), while ssp. maroccana 2n = 46+(0-2B). A new number 2n = 72, with a different grade of ploidy, was counted for G. obtusiramea. In several populations of G. pilosa the euploid number 2n = 24+(0-3B) was found; only in one population from Val D'Aosta the aneuploid numbers 2n = (40, 42), 44+(0-JB) were counted. A comparison was also made with karyological data already available for ali the Western taxa of sect. Spartioides and for G. pilosa.
