Kilian, N. & Gemeinholzer, B.: Studies in the Compositae of the Arabian Peninsula and Socotra — 7. Erythroseris, a new genus and the previously unknown sister group of Cichorium (Cichorieae subtribe Cichoriinae). — Willdenowia 37: 283–296. — ISSN 0511-9618; © 2007 BGBM Berlin-Dahlem. doi:10.3372/wi.37.37117 (available via http://dx.doi.org/)
Two species of Socotra Island and N Somalia, respectively, known as Prenanthes amabilis and P. somaliensis, are identified by molecular (ITS and matK) and morphological analyses as the closest relatives to Cichorium, hitherto considered an isolated genus of the tribe Cichorieae. To accommodate these two species, the new genus Erythroseris is established, the new combinations E. amabilis and E. somalensis are validated, and the basionym Tolpis somalensis is neotypified. Morphological differences and accordances between Cichorium and Erythroseris are discussed. It is concluded from the micromorphological results that the scaly pappus of Cichorium is homologous with the setaceous pappus as present in Erythroseris. A key to the species, illustrations of achenes, pappus and pollen, and a distribution map of the new genus are given.