Evidence for the recognition of Schoenus caespitans as a separate species from Schoenus apogon

Abstract

ABSTRACT This study examines the taxonomic rank of the New Zealand endemic sedge Schoenus caespitans. This taxon has been alternatively recognised as a separate species or as a variety of Schoenus apogon and no clear consensus on its rank has been reached. We analysed chloroplast and nuclear DNA sequences of sympatric S. caespitans and S. apogon from two populations. We found that S. caespitans and S. apogon are genetically as well as morphologically distinct in sympatry and should, therefore, be recognised as separate species. Examination of herbarium specimens indicated that the two species are morphologically distinct throughout their distributions in New Zealand. There are few recent records of S. caespitans, which is ranked as Naturally Uncommon with a Data Poor qualifier, and demographic assessments of previously recorded populations and searches for new populations of S. caespitans are required. Additional work is also needed to determine the relationships of New Zealand S. apogon and S. caespitans with populations from overseas.