Table S1: Phenotypic expressions (parental dominance (D); parental additivity (I); transgressive (T)) for the hybrid Spartina densiflora x foliosa (Sdxf) for 36 traits measured at different salinities (0.5, 10, 20 and 40 ppt) and inundation depths (shallow inundation (SI), 4.4 cm; Intermediate inundation (II), 35.5 cm; Deep inundation (DI), 55.0 cm deep). Parental taxa: S. densiflora (Sd); S. foliosa (Sf). Three-way ANOVA, salinity x inundation x taxa, P < 0.05, n = 4. Table S2: Number of individuals of Spartina densiflora x maritima (n = 4) with transgressive response for 36 traits measured at each treatment combination of salinities (0.5, 10, 20 and 40 ppt) and inundation depths (shallow inundation (SI), 4.4 cm deep; intermediate inundation (II), 35.5 cm deep; deep inundation (DI), 55.0 cm deep). Percentages of individuals are marked in bold. Figure S1: Pictures of individuals of Spartina foliosa, S. densiflora x foliosa and S. densiflora (from left to right for each inundation treatment) after 44 days under shallow (SI, 4.4 cm deep), intermediate (II, 35.5 cm deep) and deep inundation (DI, 55.0 cm deep) and exposed to (A) 0.5 ppt salinity and (B) 40 ppt salinity