Although some parts of the images are out-of-focus, these appear to be normal structures of the fern. Several fern species produce spores on special pinnae (the leaflets on the frond), including sometimes at the ends of the leaf. Pinnae bearing spores tend to be skinnier, sometimes puckered or curled, and bearing visible spore cases on their undersides, looking like dense sugar grains or dust that is usually cinnamon-brown, blackish, or tan in color.

The tan flaky residue on the main stem of the frond (terms include stipe, rachis, or petiole) also looks normal, and several fern species have this protective coating. It's usually denser as the frond is uncoiling (sometimes to the point that the whole thing looks quite fuzzy) and becomes more sparse as it expands to full size and starts wearing off.

Scale is one of the few insect pests that ferns can contract, but we don't see signs of scale in these photos. If you are uncertain, we're happy to take another look - we'd need a few more clear photos showing the leaf undersides.

Miri