PHYLOGENY AND BIOGEOGRAPHY OF PRIMULA SECT. PARRYI (PRIMULACEAE)

Primula sect. Parryi comprises five species endemic to western North America: P. parryi, P. angustifolia, P. rusbyi, P. capillaris, and P. cusickiana with four varieties. This section, derived from a clade with representatives in Asia and Europe, exemplifies a phytogeographic pattern in which a widespread species is accompanied by multiple narrow endemics. We utilized AFLPs and DNA sequences from cpDNA and nuclear internal transcribed spacer/ external transcribed spacer regions to examine the hypothesis that sect. Parryi represents a split from an ancestral lineage in Primula subgenus Auriculastrum; within the section, P. parryi was the earliest to diverge; other taxa represent allopatric speciation facilitated by Pleistocene climatic and ecological changes. An alternative hypothesis is that all or some of the endemics were derived relatively recently from within the P. parryi lineage. Results affirm monophyly of sect. Parryi and major species groups, including P. parryi. Variable relationships within the P. cusickiana complex (P. cusickiana s. l. and P. capillaris) suggest recent divergence. Phylogenetic perspectives are generally congruent and consistent with a hypothesis of allopatric speciation facilitated by Quaternary landscape changes. Section Parryi encompasses a spectrum of variation from well-defined monophyletic species to less well-differentiated taxa. Climatic predictions, limited migration potential, small populations, and reproductive restrictions are reasons for conservation concern.