Alliance (taxonomy)
It is used for any group of species,[1] genera[2] or tribes to which authors wish to refer, that have at some time provisionally been considered to be closely related.The term is often used for a group that authors are studying in further detail in order to refine the complex taxonomy.For example, a molecular phylogenetics study of the Aerides–Vanda Alliance (Orchidaceae: Epidendroideae) confirmed that the group is monophyletic, and clarified which species belong in each of the 14 genera.[4] Historically, some 19th century botanical authors used alliance to denote groups that would now be considered orders.[5] This usage is now obsolete, and the ICN (Article 17.2) specifies that such taxa are treated as orders.