Prehistoric giant swamp taro (Cyrtosperma chamissonis) from Henderson Island, southeast Polynesia

Subfossil leaf fragments of giant swamp taro (Cyrtosperma chamissonis) were recovered from archaeological contexts dating as early as A.D. 1451 (mean date) on Henderson Island (24°22'S, 128°19'W), Pitcairn group-a raised limestone (makatea) island isolated at the extreme margin of southeastern Polynesia and the Indo-West Pacific biotic province. Comparison of subfossil specimens and modern reference material from a range of known cultigens under scanning electron microscopy confirms the identification. A period of active interarchipelago voyaging between A.D. 1000 and A.D. 1500 is known from recent summaries of the geochemical analysis of exotic finegrained basalt artifacts from archaeological sites throughout Polynesia. If not an initial colonization, it is during this time that Cyrtosperma should have been introduced prehistorically to most, if not all, of the inhabitable islands of the region, especially those island groups lying to the west of Henderson. Investigation of subfossil plant remains adds another dimension to understanding plant distributions, prehistoric crop use, and subsistence practices in the Indo-Pacific region