This is a freshwater aquatic fern, with scale-like fronds 5–10 mm long, ranging in colour from green to reddish, most often reddish in strong light and in winter. They are covered in fine hairs that give it the appearance of velvet.

This is a freshwater aquatic fern, with scale-like fronds 5–10 mm long, ranging in colour from green to reddish, most often reddish in strong light and in winter. They are covered in fine hairs that give it the appearance of velvet.