Systematics of Liabum Adanson (Asteraceae, Liabeae)

Abstract

Liabum (Asteraceae), one of the most important genera of the tribe Liabeae in terms of number of species and extent of overall distribution, was the subject of a revisionary study. The genus consists of perennial herbs, subshrubs, or shrubs, rarely scandent shrubs or small trees, without latex, with opposite, tripliveined leaves, radiate, heterogamous capitula, and yellow corollas. The morphology and anatomy of Liabum were studied; in addition, a principal component analysis of 100 samples representing the morphological variation and geographic distribution of Liabum in the Caribbean was conducted, resulting in recognition of a single highly variable species, L. umbellatum. Descriptions, illustrations, and maps for each species, and the first key distinguishing the species of Liabum are presented. This revision recognizes 22 species distributed from southeastern Mexico to northwestern Argentina, and in Cuba, Jamaica, and Hispaniola, including two new species from Ecuador and Peru, Liabum dillonii D. G. Gutiérrez & Katinas and L. robinsonii D. G. Gutiérrez & Katinas, respectively. The main center of species diversity for the genus is in Peru. In addition, new synonyms are proposed, and 151 names of taxa are excluded from Liabum.