The fronds of Nephrolepis exaltata are 50-250 cm long and 6-15 cm broad, with alternate pinnae (the small "leaflets" on either side of the midrib), each pinna being 2-8 cm long.
The species has erect fronds, but Nephrolepis exaltata 'Bostoniensis' (Boston fern), has gracefully arching fronds.