Cytogenetic studies in the genus Pentaschistis (Poaceae: Arundinoideae)

Abstract

Cytogenetic studies of 45 specimens, representing 16 taxa of the genus Pentaschistis (Nees) Spach confirmed two basic chromosome numbers (x = 7, 13) for the genus. Chromosome numbers for five species and one subspecies are described for the first time, i.e. P. aimides subsp.  jugorum (n = 2x = 14). P. colorata (n = 2x = 14). P densifolia (n = x = 7), P. linui (n = 6x = ± 42), P. rigidissima (n = x = 7, n = 3x = 21) and P viscidula (n = 3x = 21). Polyploidy occurs frequently and new ploidy levels are described m four of the species, namely P airoides (Nees) Stapf subsp. airoides (n = 3x = 21), P. cir- rhulosa (Thunb.) McClean (n = x = 7), P. eriostoma (Nees) Stapf (n = 3x = 39+0-4B) and P rupestris (n = 4x = 28) The majority of species form young polyploid complexes. There seems to be no correlation between cytogenetic data and mor­phological groupings within Pentaschistis.