8645 Pilosella Hill
- Hill, Brit. Herb.: 441 (1756). - Hieracium subg. Pilosella (Hill) Gray, Nat. Arr. Brit. Pl. 2: 421 (1821).
- Hieracium sect. Piloselloidea W.D.J. Koch, Syn. Fl. Germ. Helv., ed. 2: 509 (1844).
Notes: Sennikov and Elven: There are good morphological reasons to keep Pilosella apart from Hieracium, see Sennikov and Illarionova (2002). This view was expressed already by Sell and West (1976) even if they did not apply it for Flora Europaea (possibly because of a lack of relevant name combinations in Pilosella). Pilosella and Hieracium have different modes of agamospermy (Gustafsson 1947a, 1947b etc.; Bräutigam and Greuter 2007). There are several independent and non-overlapping morphological differences. Nearly all species of, respectivelly, Hieracium and Pilosella are connected by "transitions", whereas there are no species connecting these two groups. In recent phylogenetic studies (Gaskin and Wilson 2007; Fehrer et al. 2007), Pilosella, Hieracium s. str., and Stenotheca (American "Hieracium") appears as three major branches with good support. Whether to treat them as genera or subgenera is mainly a matter of choice. The majority of recent European authors accept Pilosella (e.g., Hämet-Ahti et al. 1998; Tyler 2005; Elven et al. 2005). Strother (2006b) included Pilosella in Hieracium in the North American treatment with a few comments. Bräutigam and Greuter (2007) argued the case for acceptance of Pilosella and discussed its differences from Hieracium s. str.
The taxa of Pilosella are partly sexual, partly hybridogeneous agamosperms and then often between identifiable species (as opposed to Hieracium). As few of the assumedly hybridogeneous taxa reach the Arctic, all species are fully entered for the Checklist. Tyler (2005) found, based on allozyme variation, that the species were not clearly demarcated, with insufficient correlation between allozymes and morphology and almost no specific bands. He interpreted the pattern as resulting from considerable gene-flow among species.
Sennikov's PAF proposal of Pilosella did not include the northwestern European species. Elven has tried to add some for Iceland and Norway. The Pilosella group is currently under revision (Tyler 2001, 2005). The present account may have to be thoroughly changed in the future.
Higher Taxa
- Asteraceae [86,family]