A fern leaf is also called a frond. When a fern stem first produces a frond it appears as a brown lump poking through the soil surface. The lump becomes larger then breaks open and the coiled up frond can be seen. As the frond grows and uncoils it looks like a miniature shepherd's crook. When the frond is fully grown it may look like a huge feather. The central stem is like the shaft of a feather and the main part of the blade is divided into many pairs of green leaflets that look like the vanes.

The spores develop in brown cases on the underside of the fronds. When the spores are ready to be released the case opens. It may do this suddenly and send the spores shooting out as if an explosion had taken place.