Nomenclatural, taxonomic and biogeographic novelties in the Turkish Crataegus L. (Rosaceae-Maleae) taxa

Crataegus davisii Browicz is a later homonym of C. davisii Sarg., and the species has been renamed as Crataegus petrodavisii Donmez, nom. nov., following its acceptance as a valid species. Crataegus x yosgatica K.I.Christ. is reduced to a synonym of C. meyeri Pojark., and an emended description of the species is given here. Crataegus pseudoazarolus Popov, C. pseudoheterophylla Pojark. subsp. turcomanica (Pojark.) K.I.Christ. and Crataegus x lavallei Herincq ex Lavallee are new records for the Turkish flora. New descriptions of the taxa concerned are provided.