Morpho-functional traits influencing the fitness of highly endangered Eokochia saxicola (Guss.) Freitag & G. Kadereit (Amaranthaceae)

Eokochia saxicola (Guss.) Freitag & G. Kadereit is a very rare and endangered endemic species of Southern Italy and one of the rarest plants in Europe. It grows only on calcareous or volcanic sea cliffs and is supposed to be the remnant of an old lineage, being considered an ancestor within the Chenolea Glade (tribe Camphorosmeae). Given that data on the biology and ecology of this species are limited, the aim of this study is to increase the knowledge of reproductive and vegetative structures and to investigate the occurrence and nature of potential critical steps in the life cycle affecting the species fitness. Micro- and macro-morphology of leaves, flowers and diaspores have been analysed together with seed germination in different environmental conditions.Morphological analyses have improved the description of the species (flowers are sub-ternate, subsessile at the axils of leaves and show protogyny) and highlighted the occurrence of peculiar and interesting characteristics of the epidermis, such as the presence of superhydrophobic surfaces both on the vegetative and reproductive structures. These surfaces are discussed with respect to removing dust and salt from leaves and protecting perianth from moulds. Seed germination is inhibited even by moderate environmental salinity but readily recovers in fresh water.Results are discussed with regard to the adaptive strategy of E. saxicola to the peculiar habitat of coastal cliffs, e.g., salinity stress and geographic isolation, and to the current hypothesis on the origin of the Chenolea Glade. (C) 2015 Elsevier GmbH. All rights reserved.