Essential oil composition of Bothriochloa Kuntze (Poaceae) from South America and their chemotaxonomy

The essential oils compositions of the 13 taxa (twelve species and two varities) of Bothriochloa have been studied. Two entities are endemics: Bothriochloa eurylemma and Bothriochloa meridionalis. The other nine taxa have disjunt distribution between North and South America and are representatives of two complexes: the Bothriochloa barbinodis complex and the Bothriochloa saccharoides complex. Multivariated statistical analysis (Principal Component Analysis, Hierarchical Cluster Analysis) applied to GC–MS data seems to have systematic significance for the delimitation of the species, independently of their morphological characteristics. However, some affinities with chromosome complement and mode of reproduction (amphimixis or sexuality) can be recognized.