The identities of the component glycerol glucosides of the wall teichoic acids of Lactobacillus plantarum N.I.R.D. C106 have been confirmed by methylation analysis. These glucosides are alpha-d-glucopyranosyl-(1-->1)-l-glycerol, alpha-d-glucopyranosyl-(1-->2)-alpha-d-glucopyranosyl-(1-->1)-l-glycerol and alpha-d-glucopyranosyl-(1-->3)-alpha-d-glucopyranosyl-(1-->1)-l-glycerol. 2. These units are connected by phosphodiester groups attached to the 3(l)-hydroxyl group of glycerol and the 6-hydroxyl group of the non-reducing terminal glucose residues in the adjacent unit. 3. Concanavalin A forms a precipitate with the teichoic acid and the material so precipitated contains only the alpha-d-glucopyranosyl-(1-->2)-alpha-d-glucopyranosyl -(1-->1)-l-glycerol component. This unit is therefore present in a homogeneous polymer so that the teichoic acid is a mixture of this and of other possibly homogeneous chains containing the other two components.