Karyological and taxonomic notes on Cytisus Desf. Sect. Spartopsis Dumort. and Sect. Alburnoides DC. (Genisteae, Leguminosae) from the Iberian Peninsula and Morocco

Karyological information on Cytisus species indicates at least two chromosome numbers for most of the taxa. This instability is, a striking karyological feature of Cytisus . Chromosome numbers of taxa in Sect. Spartopsis and Sect. Alburnoides, both well represented in Morocco and the Iberian Peninsula, are presented here. We provide the first data on chromosome numbers for the Moroccan taxa: C. grandiflorus subsp. barbarus , and subsp. haplophyllus (n = 23, 2 n = 46) , C. maurus (2 n = 48), C. megalanthus ( n = 23), C. arboreus subsp. arboreus , subsp. baeticus , and subsp. catalaunicus (2 n = 50), C. valdesii ( n = 23 ). New populations from the Iberian Peninsula have been counted: C. grandiflorus subsp. grandiflorus (2 n = 46), C. scoparius subsp. scoparius ( n = 23) , C. striatus subsp. eriocarpus ( n = 23, 2 n = 46), C. multiflorus (n = 23), C. oromediterraneus ( n = 23, 24). Our data confirm the instability of the chromosome number in Cytisus . The presence of B chromosomes in C. valdesii and C. megalanthus , as well in other species, is discussed in relation to this instability and previous data. We suggest that instability of the chromosome number within a taxon, and even in the same population, may be related to the breakage of A chromosomes and the appearance of B chromosomes.