Phylogeography of a Tertiary relict plant, Meconopsis cambrica (Papaveraceae), implies the existence of northern refugia for a temperate herb

The perennial herb Meconopsis cambrica, a western European endemic, is the only European species of the otherwise Himalayan genus Meconopsis and has been interpreted as a Tertiary relict species. Using rbcL and ITS sequence variation, we date the split between M. cambrica and its sister clade Papaver s.str. to the Middle to Upper Miocene (12.8 My, 6.4-19.2 My HPD). Within M. cambrica, cpDNA sequence variation reveals the existence of two groups of populations with a comparable level of genetic variation: a northern group from Great Britain, the Massif Central, the western Pyrenees and the Iberian System, and a southern group from the central and eastern Pyrenees. Populations from the Cantabrian Mountains were found in both groups. Based on ITS sequence variation, the divergence between these two groups can be dated to 1.5 My (0.4-2.8 My HPD), and the age of the British populations is estimated as 0.37 My (0.0-0.9 My HPD). AFLP results confirm the distinctive nature of the populations fr...