Figure 1.

Time-calibrated phylogeny of one of four most-parsimonious rDNA ITS trees of the Hawaiian silversword alliance (Argyroxiphium, Dubautia, and Wilkesia) and closest continental perennial relatives in Madia and Raillardiopsis (8, 9). Outgroup tarweed taxa, Adenothamnus validus and Raillardella pringlei, are not shown. Bootstrap values are shown along branches. Consistency index = 0.81. Retention index = 0.85. The tree shown is a clade that nests within the much larger tarweed radiation (ca. 114 species in 17 genera) (25).