The precise taxonomy of the genus Allium is still poorly understood with incorrect descriptions being widespread. With over 850 species distributed over the Northern hemisphere Allium is the sole genus in the Allieae, one of four tribes of subfamily Allioideae (Amaryllidaceae). New species continue to be described[1] and Allium is both highly variable and one of the largest monocotyledonous genera,[2] but the precise taxonomy of Allium is poorly understood,[2][1] with incorrect descriptions being widespread. The difficulties arise from the fact that the genus displays considerable polymorphism and has adapted to a wide variety of habitats. Furthermore, traditional classications had been based on homoplasious characteristics (what turn out to be independently evolved similar features in species from different lineages). However, the genus has been shown to be monophyletic, containing three major clades, although some proposed subgenera are not.[2] Some progress is being made using molecular phylogenetic methods, and the internal transcribed spacer (ITS) region, including the 5.8S rDNA and the two spacers ITS1 and ITS2, is one of the more commonly used markers in the study of the differentiation of the Allium species.[1]
Allium includes a number of taxonomic groupings previously considered separate genera (Caloscordum Herb., Milula Prain and Nectaroscordum Lindl.) Allium spicatum had been treated by many authors as Milula spicata, the only species in the monospecific genus Milula. In 2000, it was shown to be embedded in Allium.[3]
- ^ a b c Deniz et al. 2015.
- ^ a b c Li et al. 2010.
- ^ Friesen et al. 2000.