Evaluating species limits and hybridization in theCarex complanatacomplex using morphology, amplified fragment length polymorphisms, and restriction fragment analysisThis paper is one of a selection of papers published in the Special Issue on Systematics Research.

Abstract

We used a combination of morphology, amplified fragment length polymorphisms (AFLP), and restriction-site data from 252 individuals from 51 populations to investigate species limits and hybridization in the Carex complanata complex. Principal coordinate analysis of the morphological data shows clear separation of entities corresponding to Carex bushii Mackenzie and Carex caroliniana Schwein. However, only leaf indumentum reliably distinguished between Carex hirsutella Mackenzie and Carex complanata Torr. & Hook. Despite this very subtle difference, AFLP data reveal very clear genetic separation of these two taxa. Contrary to the assertions of previous authors, we found no evidence of introgression among C. complanata, C. caroliniana, and C. bushii. Relatively high genetic variation within C. hirsutella may be an indication of gene-flow between this species and one or more other species, but further work is necessary to clarify this issue. We document six previously undescribed sterile or nearly sterile hybrids involving the species in this complex.