mucilage

noun

(L. mucilago: mucus) A gumlike, gelatinous, viscous, slimy substance frequently present in the cell walls of aquatic plants (as seaweeds), in the seed coats of certain other species (as legumes), and exuded by certain plants or plant organs. Mucilages are hard when dry and slimy when wet. Like gums they probably have a general protective function or serve to anchor the plant. Mucilage contains protein and polysaccharides and is similar to plant gums.