The inner and outer integuments of Erythroxylum coca are both of dermal derivation. The outer integument is initially 3 cells and later 3-5 cells thick. The inner integument is at first 3 cells thick to become multiplicative and ultimately about 20 cells thick and thus forming the greater part of the mass of the seed. The inner layer is developed as an endothelium. The nucellus is oblong by mitotic activity in the part beneath the embryo sac. The testa and legmen are crushed with the exception of the fibrous exotegmen. The flattened cells of the inner layer contain tannin. The relationship between Erythroxylaceae and Linaceae is discussed.