Willdenowia 37
Willdenowia – Annals of the Botanic Garden and
Botanical Museum Berlin-Dahlem
ISSN 0511-9618
© 2007 BGBM Berlin-Dahlem.
Bräutigam, S. & Greuter, W. 2007: A new treatment of Pilosella for the Euro-Mediterranean flora
[Notulae ad floram euro-mediterraneam pertinentes 24].
Willdenowia 37: 123-137.
doi:10.3372/wi.37.37106
Abstract
Recognising Pilosella as a genus distinct from Hieracium is justified both from a phylogenetic
point of view (a more broadly defined Hieracium, to be monophyletic, would have to include at
least two further genera along with Pilosella: Andryala and Hispidella) and for practical considerations.
In Hieracium, almost all taxa are apomicts that rarely hybridise, and whenever they do, give rise to new,
stable apomictic lines that are customarily given taxonomic recognition as species or subspecies.
In Pilosella hybridisation is frequent, gene flow between populations (however defined) is considerable,
and the recognition of microtaxa as if they were apomictic lines is unpractical. The classification here
proposed rests on a framework of twenty accepted “basic” species (some with subspecies) or species aggregates.
Hybrid progenies in which 2-3(-4) of these species or aggregates are believed to have participated are treated
as 122 “collective species”, one per known or postulated parental combination. Each of these comprises one
recognised species, or sometimes more than one when an included morphotype is stable over a significant,
coherent area, or when the offspring of a particular subspecies or microspecies combination deserves
recognition. A synopsis of the proposed classification is presented, and required new names and combinations
are validated.
Key words
Hieracium, Europe, Mediterranean, classification, nomenclature, collective species.
