Development, Diversity and Dynamics of Plant Architecture in Utricularia subgenus Polypompholyx – Towards Understanding Evolutionary Processes in the Lentibulariaceae

Abstract

AbstractTo uncover the nature of various kinds of stolons of Utricularia subgenus Polypompholyx (Lentibulariaceae) we studied branching of stolons by scanning electron microscopy, statistically investigated correlations of stolon types and other traits across 56 species, and evaluated seedling development and process morphological aspects. Some results were compared to the sister genera Pinguicula and Genlisea. A key to nine stolon types in Polypompholyx is provided. Predominant stolon types were rhizoids, runner stolons with rhizoids on nodes, and runner stolons without rhizoids on nodes but with bladders on internodes. Stolon types were taxonomically relevant and correlated to the distribution/climate. They obviously diverged with speciation events in Australia. Examined seedlings of Genlisea and Polypompholyx showed similar developmental patterns. Stolons were homologous to traps and leaves. Selected subterranean organs contained specific but similar process combinations of roots, shoots and/or leaves. We assume the Genlisea-Utricularia ancestor trap included processes of a Pinguicula root and leaf.