Relict chomophytic and chasmophytic vegetation in the shaded and water-splashed habitats of the Mediterranean, the Atlantic islands, North Africa and Middle East
Adiantetea Br.-Bl. et al. 1952
Adiantetea Br.-Bl. et al. 1952
adi01 | Zechmeister (1993) and Zechmeister & Mucina (1994) classify the contents of this class into the Montio-Cardaminetalia (Montio-Cardaminetea). Indeed these communities share many species (especially cryptogams) typical of the water-spring vegetation, but they also show ecological characteristics of chasmophytic vegetation typically classified within the Asplenietea trichomanis (substrate is raw bedrock, plants growing often in rock crevices, steep or vertical inclinations etc.). The relict character of the Adiantetea (which are also found in sheltered habitats of the North African and Arabian mountain ranges; Deil 1989, 1996, 1998) is yet another character shared with some of the Mediterranean Asplenietea units. We can presume that many of the habitats supporting Adiantetea today did not suffer from dramatic Pleistocene cyclic climatic change events (including glaciations), hence these micro-habitats might have continually supported this vegetation as remotely as the Middle and Upper Tertiary. The low species diversity and small species pool that contribute to the assembly of the Adiantetea communities make it difficult to make syntaxonomic judgements based purely on floristic-sociological criteria. It is rather its controversial transitional (between the Asplenietea and the Montio-Cardaminetea) as well as relict occurrence on a suite of endemic relicts that motivate preserving the identity of the Adiantetea as class in its own right. (L. Mucina) The name of the class was validly published for the first time in Braun-Blanquet et al. (1952) and the original diagnosis of the class contains the 'Adiantetalia Br.-Bl. 1931' comprising the 'Adiantion Br.-Bl. 1931' (both names invalidly published in Braun-Blanquet 1931). The unique association of the alliance, the 'Eucladieto-Adiantetum Br.-Bl. 1931', was validly published in Br.-Bl. et al. (1952: a synoptic table), hence the correct name of the association becomes 'Eucladio-Adiantetum Br.-Bl. in Br.-Bl. et al.1952'. The latter association is the nomenclature type of the Adiantion Br.-Bl. in Br.-Bl. et al. 1952, which in turn, is the typus the Adiantetalia Br.-Bl. in Br.-Bl. et al. 1952. (LM) The latter alliance and order are both later homonyms (ICPN art. 31) of the names 'Adiantion Br.-Bl. ex Horvatić 1934' and 'Adiantietalia Br.-Bl. ex Horvatić 1934' to which reference is not made in Br.-Bl. et al. (1952). (J.-P. Theurillat).