Botany Rules 6: Ongoing Issues--Acacia

Acacia koa, Hawaii

    I have been writing how the rules for plant names are made and how they are changed. The rules and changes are made by people. But people rarely all agree. Controversial issues dividing the members of the International Association of Plant Taxonomists (IAPT) keep cropping up. 

    The current problem is the acacias. Acacias are trees and shrubs found in the Americas, Africa and Australia, with a few in southern Asia and on islands around the world. Historically they were in one huge genus with 1,540 species, the genus Acacia. 

    It has been clear for more than a decade that the acacias are not a single group but rather five groups of similar-looking plants. The subgroups (subgenera) of Acacia are being renamed as genera in their own right, bringing the names into line with the evidence, which is both molecular and morphological. 

    The problem was and is: which plants get to be called Acacia?