Species relationships of Hieracium (Asteraceae) in British Columbia

Abstract

The morphology, cytology, reproductive behaviour, and interrelationships of seven Hieracium species in two subgenera were studied. In British Columbia the subgenus Hieracium is represented by the morphologically variable species H. umbellatum, which is triploid and apomictic. The subgenus Stenotheca is represented by H. triste, H. gracile, H. albiflorum, H. albertinum, H. cynoglossoides, and H. scouleri, all of which are diploid and amphimictic. The latter six species fall into three groups; within each of these, considerable intergradation occurs. The groups are morphologically distinct and differ in reproductive strategy but are cytogenetically similar and interfertile. Artificial hybrids between the groups have lowered pollen viability but are meiotically regular.