This fern is known to grow to heights of 10 metres (33 ft) or more (though it occasionally takes a rare creeping form). The crown is dense, and mature fronds tend to be about 4 metres (13 ft) long and have a silver-white colouration on the undersides. This distinctive silver colouration has made them useful for laying along tracks for night walking. The scales are a dark brown and are often twisted and glossy. Rhizomes very rarely prostrate, usually erect, forming a woody trunk up to 12 metres (39 ft) tall, 160 to 450 millimetres (6.3 to 17.7 in) in diameter, covered in light brown or white projecting stipe bases; bearing scales near the apex.