Geographic patterns of morphological variation in Turnera sidoides L. subsp. pinnatifida (Turneraceae)

VIVIANA GRISELDA SOLIS NEFFA

Bariloche

Congreso; VI Southern Connection Congress; 2010

Turnera sidoides is a species suitable to address some questions concerning the evolution at infraspecific level. This complex of perennial rhizomatous herbs has a marked morphological variability and is widely distributed in southern South America. It extends over S Bolivia, Paraguay and Brazil, Uruguay and Argentina, reaching 39ºS. Aiming to contribute to the understanding of the patterns of variation within this species, T. sidoides subsp. pinnatifida was selected to perform a detailed evaluation of the morphological variation along its entire distribution area. The multivariate analysis based on leaf traits and flower colour data allowed the differentiation of five morphotypes. Common-garden experiments also demonstrated that the morphological variants have a strong genetic basis. The morphotypes occur in geographically separated areas with different climatic regime, vegetation cover and soil types. Although, these results are suggestive of adaptive differentiation of subsp. pinnatifida, the intermediate degree of coincidence between morphological and bioclimatic ordinations suggests that the present-day biogeographical patterns of morphotypes are only partially influenced by current climate. Historical events may explain the origin of the five morphotypes, while the current climatic and ecological factors may be contributing to the maintenance of the morphological differentiation and the patterns of distribution of the morphotypes of T. sidoides subsp. pinnatifida.