Taxonomic revision of Ornithogalum subgen Cathissa (Salisb.) Baker (Hyacinthaceae)

As a part of a taxonomic revision of the Iberian taxa of Ornithogalum, results corresponding to O. subgen. Cathissa are reported. Quantitative and qualitative characters are studied in detail, and they are evaluated for the taxonomic value of morphological characters of the three considered taxa: O. concinnum, O. broteroi, and O. reverchonii. A complete description is presented for all accepted species, and data on their biology, habitat, and distribution are also included. Moreover, a key is provided to facilitate identification.