Taxonomy
The taxonomy of Allium is poorly understood, with incorrect descriptions being widespread. Allium spicatum has 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.
In 2006, a phylogeny of Allium was published based on the nuclear ribosomal gene ITS. The authors of this study divided Allium into 15 subgenera and 72 sections. They defined the subgenus Rhizirideum in a much narrower sense than in previous classifications.
Subsequent molecular phylogenetic studies have shown the 2006 classification is a considerable improvement over previous classifications, but some of its subgenera and sections are probably not monophyletic. One of these studies focused on the subgenus Amerallium, which is strongly supported as monophyletic. Another study focused on Allium ampeloprasum and its relatives within the section Allium of subgenus Allium. Sampling in this study was not sufficient to test the monophyly of section Allium.
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