Abstract
Allium istanbulense, a new species of Allium sect. Codonoprasum, is described and illustrated from Istanbul surroundings (European Turkey). It is a late-flowering diploid species (2n = 16), occurring in the undergrowth of oak or pine woods mainly on sandy or incoherent soils. Its morphology, karyology, leaf anatomy, seed micromorphology, ecology, conservation status and taxonomic relationships are examined. A taxonomic comparison with the most allied late flowering species of sect. Codonoprasum and identification keys of the group are also provided.