River gravel chondrilla communities

Open and often unstable assemblies of herbaceous or suffrutescent pioneering plants, rich in casual immigrants from higher altitudes, colonizing gravel beds of the montane reaches of unregulated Alpine streams, with [Chondrilla] spp., often accompanied by [Dryas octopetala], [Aethionema saxatile], [Epilobium dodonaei], [Erigeron acer], [Euphorbia cyparissias], [Fumana procumbens], [Agrostis gigantea], [Anthyllis vulneraria alpestris], [Hieracium piloselloides], [Calamagrostis pseudophragmites], and seedlings of [Salix elaeagnos], [Salix purpurea]. Because of widespread interference with natural flow regimes, these formations are gravely endangered.