Java Fern is sprouting brown stuff

Please see pic for an example of the spiky/spiraly/brown growth I have on the underside of my java fern leaves. Is this algae or spores for propagation?

I would imagine, judging from my experience, that it is the root system of new plants. These grow on the end of more mature leaves and the roots look like pieces of fuzzy brown string. Cannot really tell from your pic, but it doesn't look like any alage that I know of.

It might be your java fern dying and then reproducing. Don't throw the brown matter out, it will sprout baby java ferns soon!

yep quite normal. leave the dead leaves in place for a while until the baby plants break free by themselves.