Morphological differences of Turnera diffusa (Turneraceae) in two populations differing in rainfall at Northeastern Mexico

Abstract

Background. Plant morphology is the expression of a set of characteristics in response to environmental conditions and therefore to the availability of resources.

Questions. Are the populations of Turnera diffusa morphologically different due to climatic factors?

Species studied. Turnera diffusa, known as “damiana”.

Study site and dates. Jaumave and Güémez in Tamaulipas, Mexico; during October 2013 and April 2014.

Methods. Abiotic characteristics of study sites and morphological traits of the plants were evaluated, as well as the exposure of the plants to light, and the flowering; 15 random transects of 100 m2 each were made in each site. A multivariate analysis with linear discriminant functions was applied to determine possible differences between the two populations considering the morphological variables.

Results. The population of T. diffusa of Güémez did present higher branch density and bigger leaves than those of Jaumave, which can be related to the greater precipitation that is received in that locality in comparison with Jaumave. T. diffusa plants with higher height were found under natural shade conditions and flowering is a condition that seems to be unrelated to the exposure.

Conclusions. Populations of Turnera diffusa of Jaumave and Güémez were morphologically different.