Abstract
A phylogenetic analysis of 43 individuals using five plastid and two nuclear DNA sequence regions and morphological and chromosomal observations were used to clarify the recognition and delimitation of species in the Carex macroglossa complex (Cyperaceae). The molecular analysis resulted in two, wellsupported major clades I and II, each further consisting of two subclades A and B, and C and D, respectively. Morphologically, clade I (comprising subclades A and B) corresponded to C. macroglossa, subclade C to C. parciflora, and subclade D to C. vaniotii. All individuals of subclade A had high chromosome numbers (2n = 46–48, 50), whereas those in subclade B had lower chromosome numbers (2n = 34, 36, 38). The absence of intermediate chromosome numbers suggests reproductive isolation between individuals of subclades A and B. Our morphological observations further showed that individuals of subclade A have a style twisted at its base and short culms, whereas individuals of subclade B have a straight style and taller culms. Based on the molecular analysis in addition to the chromosomal and morphological observations, four species, C. macroglossa (subclade A), C. tsukudensis comb. & stat. nov. (subclade B), C. parciflora, and C. vaniotii were distinguished.
