(i) The plants are perennial forming a dominant flora in colder areas. (ii) Leaves are generally dimorphic, foliage and scale leaves. (iii) The foliage leaves do not have lateral veins, instead transfusion tissue occurs internally for lateral transport. (iv) Sporophylls produce strobili or cones. Flowers are absent. (v) Microsporophylls do not show distinction of filament and anther