Differentiation by psb A- trn H spacer region barcode (Genbank Accession 1230807). This barcode was analyzed in Parthenium species, P. incanum, P. tomentosum, P. schottii, P. integrifolium, hybrid AZ101 (P. argentatum × P. tomentosum) and P. argentatum lines AZ1, AZ2, AZ3, AZ4, AZ5, AZ6, Cal6, C156, C86 and cv. 11591. UPGMA in Jukes-Cantor mode was used to construct the tree, with statistical support for tree branches evaluated by bootstrap analysis (1000 replicates), indicated above the node. Minority barcodes are indicated by #'s after the name of the line. Helianthus annuus is included as an outgroup.