A TAXONOMIC ANALYSIS OF GLUCOSINOLATE-PRODUCING PLANTS, .1. PHENETICS

Similarities among taxa of glucosinolate-producing plants and putative relatives were evaluated using numerical methods applied to a dataset of 93 characters. These include anatomical and morphological (vegetative and reproductive), chromosomal, palynological, phytochemical, and ultrastructural features. Principal components and coordinates analyses reveal considerable complexity, hence little redundancy in this dataset. Cluster analyses show that glucosinolate taxa as a whole are not phenetically coherent. With or without glucosinolate characters included in the analyses, a core capparalean group comprises Brassicaceae, Capparaceae, Resedaceae, and Tovariaceae, to which are linked the non-glucosinolate Koeberlinia and the families Bataceae, Gyrostemonaceae, and Salvadoraceae but not Moringaceae. Based on a sparser dataset, Drypetes clusters with Euphorbiaceae; Akania and Bretschneidera cluster together but not close to Sapindaceae; Pentadiplandra is too poorly known to be placed with confidence. Caricaceae, Limnanthaceae, Moringaceae, and Tropaeolaceae remain problematic.