ROALSON, ERIC H. Rancho Santa Ana Botanic Garden and The Claremont Graduate University, 1500 N. College Ave., Claremont, CA 91711. - Molecular phylogenetic studies in Carex section Acrocystis (Cyperaceae): evidence from nuclear Adh and ITS genic regions.
Carex section Acrocystis (Cyperaceae) traditionally has
included ca. 45 species. Recent studies have suggested that a “core”
group of Acrocystis species forms a monophyletic group, while
other species are more closely related to other sections. This core
group includes all North American Acrocystis species and some
but not all Eurasian members. Taxonomists have recognized several
species complexes in North American Acrocystis, with several
“orphan” species not delt with in these species complexes. The
complexes that have been defined include the “Carex
pensylvanica complex,” the “Carex nigromarginata complex,”
the “Carex deflexa complex,” and the “Carex umbellata
complex”. Taxa not included in these complexes are Carex
novae-angliae, C. turbinata, C. leucodonta, C.
communis, C. globosa, C. brainerdii, and C.
serpenticola. How these complexes and orphan species are related
has not been addressed explicitly, and none of the North American
species have been explicitly compared with Eurasian or South American
members of Acrocystis, with few exceptions. The study
presented here explores relationships within North American members of
Carex section Acrocystis and related Eurasian species
and addresses biogeographic patterns of diversification using nuclear
Adh genic regions and the nrDNA ITS region.
Key words: Acrocystis, Adh, biogeography, Carex, Cyperaceae, ITS