Willdenowia 36
Willdenowia – Annals of the Botanic Garden and
Botanical Museum Berlin-Dahlem
ISSN 0511-9618
© 2006 BGBM Berlin-Dahlem.
Ehrendorfer, F. & Guo, Y.-P.: Multidisciplinary studies on Achillea sensu lato
(Compositae-Anthemideae): new data on systematics and phylogeography.
Willdenowia 36 (Special Issue): 69-87.
doi:10.3372/wi.36.36105
Abstract
On the basis of extended DNA sequences (nrITS, cptrnL-F) and
other new evidence present know– ledge on the differentiation of the
northern hemisphere Compositae-Anthemideae genus Achillea
in time and space is surveyed. Evidence is presented for a wide
circumscription of the genus with 110-140 species. This includes the
former unispecific genera Otanthus and Leucocyclus,
which have originated from ancestors of the basalmost clade of Achillea,
the xerophytic A. sect. Babounya s.l. (incl. sect.
Arthrolepis and Santolinoideae). Maps show the
predominantly SW Asian distribution of the section and its
derivative, A. (sect. Otanthus) maritima, a
psammophyte of the Mediterranean and Atlantic coasts. Through taxa
from the Caucasus differentiation has proceeded from A.
sect. Babounya-like ancestors to the Eurasian and more meso– and
hygrophytic 2x members of A. sect. Ptarmica s.s. They are linked
with 2x A. asiatica (A. millefolium agg.) by the
hybrid 4x A. alpina agg., which has expanded across northern
North America. A. sect. Anthemoideae s.l. consists
of several distinct clades distributed in the mountain systems of NW
Anatolia, the Balkans, Carpathians, Alps, Apennines and E Pyrenees.
This section was formerly combined with A. sect. Ptarmica
but is closer to the following section and may be polyphyletic. A.
sect. Achillea includes closely related taxa with white and
yellow(ish) ligulate flowers (the latter formerly separated as A.
sect. Filipendulinae). Members of the section have
differentiated from a centre of diversity in dry habitats of SE
Europe, partly into uniform 2x species, partly into polymorphic and
polyploid species groups. "Crown group" of the genus and
section is A. millefolium agg., a strongly diversified
polyploid complex. Its basal 2x species exhibit a vicarious and
sometimes relic differentiation pattern. They are connected in a
complex way to several parallel and reticulate lines of 4x, 6x and
8x taxa, which are partly very expansive. From 4x A. asiatica-like
ancestors in E Siberia the 4x and 6x A. borealis has
successfully radiated into many ecological niches in North America
and 6x A. millefolium s.s. has become a cosmopolitan weed.
Key words:
nr + cpDNA, polyploidy, ecological radiation, Asteraceae,
Leucocyclus, Otanthus.
