A re-evaluation of species limits in Chaetobromus (Danthonieae: Poaceae)

Past changes in the taxonomy of Chaetobromus, a Cape grass with considerable fodder potential, reflect a history of instability due to inadequate past sampling and intergradation among taxa in most characters. This biosystematic study differs from earlier investigations by its much more intensive approach to sampling, taking into consideration inter-and intrapopulational variation in 75 anatomical, morphological and cytological characters, across a total of 169 samples. Both phenetic methods and population aggregation analysis revealed the existence of three major groups, approximating three formerly described taxa and reflecting divergent ecological strategies in Chaetobromus. However, continuity among groups in most characters and a lack of clear-cut diagnostic field characters argues against their recognition at species level. Thus, Chaetobromus is here described as monotypic, the type species, C. involucratus, comprising three subspecies C. involucratus ssp. involucratus, C. involucratus ssp. sericeus and C. involucratus ssp. dregeanus.