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 con troversial. Whereas some authors consider O. cumana as an infraspecific tax on of O. cernua, others Ir eat it a?: a separate species. Furthermore, the nomenclature of the sunflower broomrape is unclear, and Loth names are foun d without qualification in the literature. The objective of the present stu dy has been to evaluate the distribution, morphology, and ecology of O. cer nua and O. cumana in the Iberian Peninsula, as well as their seed oil fatty acid profile, which is a trait of gear chemotaxonomic value. O. cernua was found parasitizing wild Compositae, mainly Artemisia spp., whereas O. cuma na was exclusively found on cultivated sunflower. Both species clearly diff er in morphological traits, especially plant height and build, length and s tructure of the inflorescence, corolla length and colour. Both species are characterized by contrasting seed oil fatty acid profits, with high oleic a cid concentration in O. cernua and high linoleic acid concentration in O. c umana. The evaluation of both taxa in the Iberian Peninsula gives additiona l support to those authors that treat them as separate species. (C) 2000 Th e Linnean Society of London.