The Probert Encyclopaedia of Nature

MUCILAGE

Mucilage is a gum-like substance frequently present in the cell walls of aquatic plants and in the seed coats of certain other species. Mucilages are hard when dry and slimy when wet. Like gums they probably have a general protective function or serve to anchor the plant. Some organisms including certain bacteria are completely covered with mucilage and in such cases it probably prevents water loss.
Research Mucilage