Comparative studies on Orobanche cernua L. and O. cumana Wallr. (Orobanchaceae) in the Iberian Peninsula

The systematic treatment of Orobanche cumana Wallr. and O. cernua L. is controversial. Whereas some authors consider O. cumana as an infraspecific taxon of O. cernua , others treat it as a separate species. Furthermore, the nomenclature of the sunflower broomrape is unclear, and both names arc found without qualification in the literature. The objective of the present study has been to evaluate the distribution, morphology, and ecology of O. cernua and O. cumana in the Iberian Peninsula, as well as their seed oil fatty acid profile, which is a trait of great chemotaxonomic value. O. cernua was found parasitizing wild Compositac, mainly Artemisia spp., whereas O. cumana was exclusively found on cultivated sunflower. Both species clearly differ in morphological traits, especially plant height and build, length and structure of the inflorescence, corolla length and colour. Both species are characterized by contrasting seed oil fatty acid profiles, with high oleic acid concentration in O. cernua and high linoleic acid concentration in O. cumana. The evaluation of both taxa in the Iberian Peninsula gives additional support to those authors that treat them as separate species.