The evolutionary patterns of the plant family Amaranthaceae on the Galapagos and Hawaiian Islands

Lithophila and Blutaparon. Morphological features suggest that the group of about nine endemic species of Alternanthera can be traced back to two or three original colonization events. Several infraspecific taxa have been recognized but the current classification should be regarded as tentative and further studies based on molecular data are needed. In the Hawaiian Islands the subfamily Amaranthoideae has differentiated, with one genus, Nototrichium, endemic with three species. The genus Charpentiera has five endemic species in Hawaii and one species in the Austral Islands. The higher level of endemism in Hawaii as compared with that in the Galapagos stems from the combined effects of the more isolated geographical position, the more varied ecological conditions, and the greater geological age of the Hawaiian chain.