NYFFELER, RETO* AND URS EGGLI. Harvard University Herbaria, Cambridge, MA 02138; Sukkulenten-Sammlung, CH-8002 Zurich, Switzerland. - Phylogenetic relationships and diversification of the columnar and globular cacti of Chile (Cactaceae - Cactoideae).
For Chile Hunt (1999; CITES Cactaceae Checklist) recognizes 11 genera
and about 80 species of Cactoideae (Cactaceae), of which six genera
(Austrocactus, Copiapoa, Corryocactus,
Eriosyce s.lat., Eulychnia, and Neowerdermannia)
and about 65 species are traditionally regarded as closely related and
referred to the tribe Notocacteae (Barthlott & Hunt 1993; Families and
Genera of Flowering Plants). Molecular phylogenetic analyses based on
chloroplast DNA markers (trnK intron, matK,
trnL-trnF intron and spacer), however, reveal that these
genera in fact are members of three different major clades of
Cactoideae. Austrocactus, Eulychnia, and
Corryocactus are related to basically West Andean
representatives of the tribes Browningieae (excl. Browningia)
as well as the Central and North American Hylocereeae, and
Pachycereeae. Copiapoa represents a distinct basal lineage
within Cactoideae without any obvious close relatives. Finally,
Eriosyce and Neowerdermannia are related to the East
Andean genus Parodia s.lat. These findings indicate that the
various similarities in different types of growth forms and related
vegetative characters in the two most diverse Chilean genera,
Copiapoa and Eriosyce, represent striking convergences.
Biogeographically the cactus flora of Chile falls into two distinct
parts with minimal overlap, (1) a narrow strip along the coast of the
central and northern half of the country, comprising the coastal
cordillera as well as some of the major inland valleys, and (2) the W
slopes of the main cordillera of the extreme NE of the country.
Representatives of the former area are Austrocactus,
Copiapoa, Echinopsis, Eriosyce, and
Eulychnia, while the genera Browningia,
Corryocactus, Neowerdermannia, Oreocereus, and
Weberbauerocereus are only present in the latter area. The
exception to the rule is Haageocereus which is present with one
representative in each of the two areas and Echinopsis
atacamensis which occurs in area 2.
Key words: biogeography, Cactaceae, cacti, Cactoideae, Chile, phylogenetics