This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol1", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Perennial herbaceous plants rooting in mud, with slender creeping root-stocks and 2- or 4-foliolate or filiform leaves. Asexual propagation consisting of sporo-carps borne on peduncles which rise from the rootstock near the leaf-stalk or are consolidated with it, containing both megaspores and microspores. The mega-spores germinate into prothallia which bear mostly archegonia, while the microspores grow into prothallia bearing the antheridia.
Three genera and some 60 species of wide distribution known as Pepper-worts.