FIG 5.

Compatibility patterns between the plant-trapping species and the spore-negative (A) and spore-positive (B) soils used in the assays. The compatibility between the 3 trapping species (white circles) Alnus glutinosa (Ag), Alnus incana (Ai), and Alnus viridis (Av), and the 6 alder stand soils (gray squares) differing in the indigenous host species (A. glutinosa, A. incana, or A. viridis) is symbolized by a continuous line (presence of compatible strains and formation of mature nodules). The incompatibility is symbolized by a dotted gray line (impeded prenodules and no compatible strain trapped).