A fossil-calibrated relaxed clock for <i>Ephedra</i> indicates an Oligocene age for the divergence of Asian and New World clades and Miocene dispersal into South America

Stefanie M. ICKERT-BOND, Catarina RYDIN, Susanne S. RENNER

Journal of Systematics and Evolution . 2009, (5): 444 -456 . DOI: 10.1111/j.1759-6831.2009.00053.x