families of ferns and fern allies

aquatic or marsh-growing fern allies; known to have existed since the Cenozoic; sometimes included in Lycopodiales

type and genus of the Isoetaceae and sole extant genus of the order Isoetales

aquatic or marsh-growing fern allies; known to have existed since the Cenozoic; sometimes included in Lycopodiales

type and genus of the Isoetaceae and sole extant genus of the order Isoetales