Biodeography

Origins of the Southern Hemisphere flora

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Science  02 Jan 2015:
Vol. 347, Issue 6217, pp. 39-40
DOI: 10.1126/science.347.6217.39-b

Which plants of the Southern Hemisphere represent descendants of the ancient flora of Gondwana, the southerly part of the supercontinent Pangaea? Evidence from molecular clocks suggests that many plant lineages descended from a more recent common ancestor. Wilf and Escapa challenge this view by comparing molecular origin dates with fossil dates for groups of plants in Patagonia, such as cycads, that are incontrovertibly Gondwanan. They find that the molecular dates are artificially recent even for these ancient groups, and are a poor match for the reliable fossil dates. These findings suggest that biogeographers may have to temper reliance on molecular evidence for determining how flora dispersed.

New Phytol. 10.1111/nph.13114 (2014).

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