The unbearable uncertainty of Bayesian divergence time estimation Tertiary montane origin of the Central Asian flora, evidence inferred from cpDNA sequences of Atraphaxis (Polygonaceae) Molecular Evolutionary Patterns of the psbA Gene in Gymnosperms Adaptive Evolution of the rbcL Gene in Pteridaceous Ferns A fossil-calibrated relaxed clock for Ephedra indicates an Oligocene age for the divergence of Asian and New World clades and Miocene dispersal into South America Divergence time estimates for major lineages of Cupressaceae (s. l.)