Correct species identification, taxonomic interpretation of the variation patterns, monographic treatments of selected species groups and Hieracium treatments for standard Floras and Determination keys form the basis for any further work on this complicated group.
Breeding modes, ploidy levels and environmental factors have a strong impact on the structure of an apomictic complex and are essential for understanding speciation processes.
Molecular approaches substantially contribute to understanding of the genus at clone, population, species and (sub)tribe level. Methods include DNA fingerprinting, chloroplast DNA haplotyping, and multi-gene sequencing.
In Hieracium s.l., DNA content is known to differ very much between subgenera and to a lesser extent also within subgenera. Within-subgenus variation can in some cases be used for the identification of hybrids. Phylogenetic patterns of DNA content and its correlates are currently under investigation.