Phylogeny of Carpha and related genera (Schoeneae, Cyperaceae) inferred from morphological and molecular data

Abstract

The limits, definitions and relationships of Carpha have been controversial and unclear. This study using cladistic analyses of morphological and combined morphological and molecular data indicates that: (1) Carpha sensu latu is paraphyletic and its species form two clades, consistent with the definitions of Carpha sensu stricto and Asterochaete respectively (i.e. the data support the division of Carpha sensu latu into two genera: Carpha sensu stricto and Asterochaete); (2) the morphological data show a high degree of homoplasy within Schoeneae; (3) Schoeneae is not a monophyletic tribe; (4) Schoenus and Tricostularia are polyphyletic; (5) it is better to place Schoenoides back in Oreobolus; (6) separation of Capeobolus brevicaulis from Costularia or Tetraria is supported; and (7) both genera Costularia and Tetraria should be maintained. The study resolves some phylogenetic relationships between Carpha and its relatives. Many aspects of these relationships are in agreement with previous studies, but some of these relationships have no support. The study also resolves the phylogenetic relationships of species of Carpha, although with lack of support for some clades, highlighting the need for other sources of data.