Pollen and chromosome studies in Hieracium sect. Alpestria (Asteraceae)

Abstract

Potential pollen viability has been investigated in British apomictic Hieracium section Alpestria and related species using Alexander's Stain. New and existing chromosome counts are given. Some species produced no pollen, others varied in the amount they produced, and a few species consistently produced reasonable quantities. The three triploid section Alpestria species produced very little or no pollen, whilst the amount produced by the tetraploids varied widely. Section Alpestria species had significantly lower pollen viability than the non-section Alpestria species. The generally low pollen production in most species of section Alpestria is consistent with them being of hybrid origin.