Cytogenetic analyses as clarifying tools for taxonomy of the genus Callisia Loefl. (Commelinaceae)

Abstract

Chromosome numbers, karyotypes and meiotic behaviour in 10 populations belonging to two species of Callisia Loefl. from Northeast
Argentina have been studied. Callisia repens showed a basic number of x = 6 and that of C. monandra was x = 7. Both species were
diploids and this is the first report of the chromosome numbers for Argentinean populations: C. repens, 2n = 2x = 12 and C. monandra
2n = 2x = 14. The karyotype descriptions of C. repens (2 m + 2 sm + 6 st + 2 t) and C. monandra (6 m + 4 sm + 4 st) are also reported
here for the first time for both species. Chromosomes behaved regularly at meiosis, pair as bivalents and produced viable pollen in the
Callisia accessions studied. Chiasmata frequency and distribution are reported and this meiotic analysis constituted a novelty for each
species. The information provided in this paper is useful for the cytogenetics diagnosis of the genus and the subtribe and contribute
to understand relationships between taxa.