Morphological Variability of Halophytes: Salicornioideae on Iberian Peninsula

Abstract

The Salicornioideae subfamily of Chenopodiaceae is distributed worldwide in coastal and inland saline habitats. It comprises a highly specialized flora adapted to an extreme environment due to its salinity, and its morphological structures are repeated as a form of adaptation in the main taxa. This fact hinders its taxonomic study. Members of this subfamily are usually dominant in halophilic vegetation communities, and the diversity of species in the Iberian Peninsula is summarized in the following genera: Arthrocnemum Moq., Halopeplis Bunge ex Ung.-Sternb., Halocnemum M. Bieb., Microcnemum Ung.-Sternb., Salicornia L., and Sarcocornia A. J. Scott. Its macromorphological and micromorphological characters are described from its vegetative structures, flowers, fruits, and seeds. The flower morphology of its perianth, anthers, ovary, style, and stigmas is thoroughly analyzed and illustrated for the first time; likewise, micromorphological data are provided with a high taxonomic value, obtained by scanning and transmission electronic microscopy (SEM and TEM) techniques, especially focused on the ornamentationof the seeds and other anatomical characters in leaf tissues, fleshy stems, and flowers. Our study improves the definition of each of the halophilic genera in the Iberian Peninsula and provides keys for the correct differentiation up to the species level.