Morphological characterization of Conyza blakei, Conyza bonariensis var. bonariensis, Conyza sumatrensis var. sumatrensis and Conyza lorentzii in the southeast of Buenos Aires (Argentine).

Abstract

Morphological characterization of Conyza blakei, Conyza bonariensis var. bonariensis, Conyza sumatrensis var. sumatrensis and Conyza lorentzii in the southeast of Buenos Aires (Argentine). The genus Conyza Less. includes ruderal species, which grow of ruderal habitat, roadsides and railways. They have also been cited as pasture weeds, annual and perennial crops under direct sowing (SD) systems, adapting to these slightly disturbed environments since they are sensitive to soil removal. The taxonomic identification of Conyza species linked to morphological characters is difficult in vegetative stages, since this genus has highly related and polymorphic species. With the objective of morphologically characterizing Conyza blakei, C. bonariensis var. bonariensis, C. lorentzii and C. sumatrensis var. sumatrensis were recorded 19 morphological characters (12 vegetative and 7 reproductive) qualitative and quantitative, in 35 plants of each species. These characters were analyzed by Multivariate Analysis (Analysis of Components and Main Coordinates). The morphological characterization made it possible to detect phenotypic differences between the Conyza species analyzed. The analysis of main coordinates allowed to differentiate the species both at a reproductive and vegetative level, while the analysis of main components only allowed to differentiate the species in reproductive stage.