Resumen de "Centaurea" subg. "centaurea" ("Compositae"): delimitation and distribution of sections and subsections
On the basis of morphological features, three sections can be distinguished within Centaidrea subg. Centaurea, two of which comprise two species each, whereas the third is polymorphic and includes the remaining 28 species, here assigned to five subsections. For sectional delimitation, characters of the pappus, cypsela and corolla of marginal flowers proved to be most useful. Subsections are defined mainly by size and shape of the capitulum, quality of the involucral bracts and their appendage, and flower size and colour. The two small sections are confined to the Ibe-ro-Maghrebine area in the SW Mediterranean: Centaurea sect. Vicentinae two species) is endemic to S.W. Portugal. C. sect. Africanae (2 species) ranges from Galicia through Portugal, S. Spain and the Maghreb countries to W. Sicily. C. sect. Centaurea extends from S. Europe to S.W. and Middle Asia. Two of its species, purple-flowered and mesophilous, form C. subsect. Centaurea, a clear-cut, N.E. Mediterranean to on with a disjunct relict distribution in S. Italy, ?Albania, S.W. Bulgaria, the N. Peloponnisos, and N.W. Anatolia. The four other are more xeromorphic, steppe-inhabiting, and yellow-flowered. C, subsect. Ruthenicae (14 species) is widespread, ranging from N.E.Spain through S. Europe and Anatolia east to Mongolia and N.W. China; Cr subsect. Aralo-caspicae (5 species) is centred on Kazakhstan and neighbouring areas; C. subsect. Turkestanicae (1 species) is confined to S.E. Kazakhstan and N.E. Afghanistan; and C. subsect. Iranicae (6 species) is found throughout the northern half of the Flora itanica area, just extending westward into the Caucasus. Apart from the presumably ancient stock of purple-flowered, mesophilous Mediterranean representatives, the diversification of the group probably has its roots in some local, hardly xeromorphic W. Anatolian endemics and took place in the realm of primary steppes that covered vast land surfaces in S.W. Eurasia in the geological past.
