This is a common fern that forms large clumps in freshwater swamps, north from Royal N.P. At Tumbi Wetlands Bushcare it is seen growing with the vigorously creeping Persicaria strigosa (Note its small white flower in the top right quarter of the photo) over the area of almost permanent water.
This fern has long-creeping rhizomes, sparsely covered with scales. Fronds are erect, to about 1 m high; stalk of the frond is up to 45 cm long, dark at the base, pale and lightly flushed with red above; the blade of the frond is usually 30 to 50 cm long and 15 to 30 mm wide and quite leathery.
Sori usually form a row around the margin of each segment as shown in the middle section of the photo.