The identity of Vernonia setososquamosa (Asteraceae, Vernonieae): chromosomal and palynological evidence.

Abstract

Vernonia setososquamosa (Asteraceae, Vernonieae) has been considered by several authors as a synonym of V. remotiflora, as a variety of this taxon or a quite different, independent species. We analyzed chromosome and pollen morphology of both entities looking for information to clarify the status of V. setososquamosa. The latter taxon showed a somatic chromosome number of 2n=2x=30 with the karyotype composed of 22m + 6sm + 2st, while on the other hand V. remotiflora presented 2n=2x=28 and a karyotype formula having 22m + 4sm + 2st. The pollen of both entities was tricolporate, echinolophate, with lacunae disposed in a regular pattern; however, V. setososquamosa presented polar lacunae, whereas V. remotiflora did not. The results support the treatment of V. setososquamosa and V. remotiflora as different species.