Heller et al. 2015 (Conference Paper) Tillandsia

Tillandsia usneoides: why is the species so morphologically variable?

Author(s):—S. Heller, J. Paule & G. Zizka in Benko-Iseppon, A.M.; Alves, M. & Louzada, R. (2015) An overview and abstracts of the First World Congress on Bromeliaceae Evolution. Rodriguésia 66(2): A1-A66.

Publication:— (2015).

Abstract:—Tillandsia usneoides is the most widely distributed species of the family Bromeliaceae (Poales). It ranges fromthe southeastern United States to Argentina and Chile. Tillandsia usneoides grows as an epiphyte with missingaerial 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 tofive varieties or subspecies. Morphotypes have been shown to be stable in cultivation while growing under sameconditions, excluding phenotypic plasticity. In order to investigate possible reasons for the variation, the relativegenome 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 tothe morphological differences (i.e. five morphotypes) and reflected the north - south distribution gradient wasdetected. However, observed variation could not be attributed to any particular climatic factor.

Keywords:—Genome Size; Morphotype; Geographical Distribution.