A description is given of the floristic composition of communities with Hordeum marinum in the South-west Netherlands. This reveals that this species, one of the character-taxa of the alliance Saginion maritimae, is especially represented in transition situations towards saline habitats with environmental instability through treading, sudden inundations and drainage, embankment, etc. Permanent plot studies showed great resemblance in succession during recovery of damaged vegetation. Hordeum manifests itself in the early developmental stages, together with Parapholis strigosa. Ecological affinities between the Saginion species are discussed in relation to salinity and silt content of the soil. Contrary to the other species, H. marinum prefers high salinities combined with a relatively high silt content of the sandy substrate.