''Callicephalus'' is a

monotypic genus In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispe ...

of flowering plants in the family

Asteraceae The family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the order Asterales. Commonly referred to as the aster, daisy, composite, or sunflower family, Compositae ...

, containing the single species ''Callicephalus nitens''. It is native to the middle and low mountains of the

Caucasus The Caucasus () or Caucasia (), is a region between the Black Sea and the Caspian Sea, mainly comprising Armenia, Azerbaijan, Georgia (country), Georgia, and parts of Southern Russia. The Caucasus Mountains, including the Greater Caucasus range ...

,Hidalgo, O., et al. (2006)
Phylogeny of ''Rhaponticum'' (Asteraceae, Cardueae–Centaureinae) and related genera inferred from nuclear and chloroplast DNA sequence data: taxonomic and biogeographic implications.
''Annals of Botany'' 97(5), 705-14. where it has been recorded in

Armenia Armenia (), , group=pron officially the Republic of Armenia,, is a landlocked country in the Armenian Highlands of Western Asia.The UNbr>classification of world regions places Armenia in Western Asia; the CIA World Factbook , , and ...

Azerbaijan Azerbaijan (, ; az, Azərbaycan ), officially the Republic of Azerbaijan, , also sometimes officially called the Azerbaijan Republic is a transcontinental country located at the boundary of Eastern Europe and Western Asia. It is a part of th ...

Georgia Georgia most commonly refers to: * Georgia (country), a country in the Caucasus region of Eurasia * Georgia (U.S. state), a state in the Southeast United States Georgia may also refer to: Places Historical states and entities * Related to t ...

Russia Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its internationally recognised territory covering , and encompassing one-eigh ...

, and

Turkey Turkey ( tr, Türkiye ), officially the Republic of Türkiye ( tr, Türkiye Cumhuriyeti, links=no ), is a list of transcontinental countries, transcontinental country located mainly on the Anatolia, Anatolian Peninsula in Western Asia, with ...

.''Callicephalus nitens'' occurrence.
Euro+Med PlantBase. 2006. The genus is considered part of the ''

Rhaponticum ''Rhaponticum'' is a genus of flowering plants in the tribe Cardueae within the family Asteraceae. Description ''Rhaponticum'' species are perennial herbaceous plants with simple, rarely branched stems. The leaves are simple to pinnatif ...

'' group in the Asteraceae tribe

Cardueae The Cardueae are a tribe of flowering plants in the daisy family (Asteraceae) and the subfamily Carduoideae. Most of them are commonly known as thistles; four of the best known genera are '' Carduus'', ''Cynara'' (containing the widely eaten art ...

, but according to molecular analyses it has no close relatives. Its isolation in the

phylogeny A phylogenetic tree (also phylogeny or evolutionary tree Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA.) is a branching diagram or a tree showing the evolutionary relationships among various biological spe ...

of the tribe suggests it is a

relict A relict is a surviving remnant of a natural phenomenon. Biology A relict (or relic) is an organism that at an earlier time was abundant in a large area but now occurs at only one or a few small areas. Geology and geomorphology In geology, a r ...

taxon, one of many relict plants that grow in the Caucasus.

References

Further reading