Dues noves comunitats de Thero-Brachypodion a les Terres Catalanes

Abstract

Two new therophytic populations are described: Clypeolo-Psiluretum and Brachypodio- Stipetum euphrasio-centaurietosum. The former settles on the most superficial soils on calcareous hills of the Noguera country, an area bearing a rather continental dry Mediterranean climate; it is a pasture almost completely built by small annual plants, with a short spring period of main activity, ending in june. According to its floristic features, as well as to its structure and behaviour, it is related to the continental Iberian sub-alliance Asterisco-Velezienion. The other community grows in a. sub-Mediterranean area around Vic-, under a moister and colder general climate, but also on superficial calcareous soils. In this case, the therophytes are accompanied by several cespitose and chamaephytic plants, but no perennial grass has a general dominance. Although owning some floristic particularities, this new community can be related to (as a new sub-association) the Brachypodio-Stipetum, a previously known grassland in which Stipa Iberica usually covers most of the surface, allowing to grow only a few therophytes.