Tangena is the name given in the highland (official) dialect of the Malagasy language to an indigenous tree (Tanghinia venenifera) distinguished by the high toxicity of the nuts it produces, which have been used historically on the island of Madagascar for trials by ordeal to determine the guilt or innocence of an accused party. The tradition of the tangena ordeal, which has taken various forms over time, dates to at least the 16th century in Imerina, the central highland kingdom that would eventually come to rule the population of nearly the entire island four hundred years later.