Chromosome studies of some species of Vernonanthura and Vernonia (Asteraceae, Vernonieae).
VEGA, A. J.; DEMATTEIS, M.
UNIV FLORENCE BOTANY INST
Lugar: London; Año: 2012 vol. 65 p. 271 - 275
Abstract The chromosome numbers of eighteen populations belonging to ten species of Vernonanthura H.Rob. and one species of Vernonia Schreb. (Vernonieae, Asteraceae) from South America were determined. First chromosome counts are presented for three taxa: Vernonanthura lucida (Less.) H.Rob. (n=17, 2n=34), V. oligactoides (Less.) H.Rob. (n=17, 2n=34) and V. pseudolinearifolia (Hieron.) Vega et Dematt. (2n=34). In addition, a new cytotype is reported for Vernonia echioides Less. (2n=34), a widely distributed species in which only tetraploid populations (n=34, 2n=68) were recorded at the present. The chromosome numbers found in Vernonanthura amplexicaulis (R.E.Fr.) H.Rob. (2n=34), V. chamaedrys (n=17, 2n=34), V. ferruginea (Less.) H.Rob. (2n=34), V. loretensis (Hieron.) H.Rob. (2n=34), V. nudiflora (Less.) H.Rob. (2n=34), V. squamulosa (Hook. et Arn.) H.Rob. (n=17, 2n=34), V. tweediana (Baker) H.Rob. (2n=34) and Vernonia echioides (n=34) are in agreement with previous records for these species. All the species of Vernonanthura and Vernonia analyzed here showed basic number x2=17 and almost all them were diploid with 2n=34. The single exception was Vernonia echioides which showed diploid (2n=34) and tetraploid (2n=68) populations.