In Chlorophyceae, the cell wall is made up of cellulose. In Rhodophyceae, the cell wall is made up of cellulose, pectin and polysulphate esters. In Phaeophyceae, the cell wall is made up of cellulose and algin. Gymnosperms are heterosporous, and most of the Pteridophytes are homosporous, and some are heterosporous like Selaginella and Salvinia. Both these plants produce two kinds of spores, macro (large) and micro (small) spores showing a tendency towards seed formation.