A new western Mediterranean species of Cuscuta (Convolvulaceae) confirms the presence of holocentric chromosomes in subgenus Cuscuta

Cuscuta nivea, a new western Mediterranean species of Cuscuta L. subgenus Cuscuta (Convolvulaceae) is described and illustrated for plants traditionally included in C. planiflora Ten. and sometimes recognized as C. planiflora var. algeriana Yunck., or the illegitimate C. cuspidata Pomel. The morphological, cytological and ecological features that allow it to be distinguished from the morphologically most similar plants, described as C. planiflora var. papillosa Engelm., are exposed. The chromosome numbers 2n = 18 and 2n = 20 are found for the new species and 2n= 34 for the papillate forms of C. planiflora Ten. The presence of holocentric chromosomes is recorded, which confirms this type of chromosome as a synapomorphy for Cuscuta subgenus Cuscuta.