Tillandsia usneoides: why is the species so morphologically variable? Talk. In Benko-Iseppon, A.M., Alves, M., Louzada, R. [eds]: Abstracts of the conferences, symposia, oral presentations and poster presentations performed during the 1st World Congress on Bromeliaceae Evolution, March 2015 (Brazil)

Abstract

Tillandsia usneoides is the most widely distributed species of the family Bromeliaceae (Poales). It ranges from the southeastern United States to Argentina and Chile. Tillandsia usneoides grows as an epiphyte with missing aerial roots and is dispersed by seeds as well as by fragments of the plant. Within the species, striking morphological differences can be observed as far as size characters are concerned and previous authors recognized up to five varieties or subspecies. Morphotypes have been shown to be stable in cultivation while growing under same conditions, excluding phenotypic plasticity. In order to investigate possible reasons for the variation, the relative genome size of 75 specimens covering the whole distribution range was measured and combined with morphological, distributional and climatic data. Significant variation in the relative genome size which corresponded to the morphological differences (i.e. five morphotypes) and reflected the north - south distribution gradient was detected. However, observed variation could not be attributed to any particular climatic factor.