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..
Climbing Fern Family. Plants with erect, simple, pinnate or dichotomous, or vine-like, twining, elongate leaves, with stalked, alternate, paired and mostly palmately lobed or pinnate leafy divisions. Sporanges borne in double rows on narrow specialized lobes or segments, obovoid, pyriform or globose, sessile, provided with a transverse apical ring and opening vertically by a longitudinal slit.
Genera 4 or more; species about 125, mainly tropical.
Leaves short, tufted, rigid.
Leaves elongate, climbing.