Um, it helps by being a better picture but I have absolutely no idea what those are. They look pretty dang weird! Are you sure that stuff is 'alive'? It kinda looks like some type of mulch but no, because you said that they were on the crown of fern between fronds. Actually, that doesn't make sense. The fronds are the leaves. Not sure what the 'crown' is.
I can tell you that your fern doesn't look like an Autumn Fern. Here's a link to the Plants Database page on Autumn ferns.
Autumn Shield Fern (Dryopteris erythrosora)
Those little leaves look very familiar but I can't come up with a name. One of the local nurseries I go to has a large selection of ferns and I love to cruise by them. There's only a few that will grow for where I live, Autumn fern being one of them, so I look but save my $$.
Is this planted in a new bed or one that was already there? Not that it matters if you picked those little aliens off the ferns. I just keep thinking they look like mulch. But you are absolutely right that most ferns like some shade and some moisture. And what is nice is that I'm seeing that you have multiple stems which tells me your fern has been growing.
So . . . I'm going to think out loud here. The frond (leaf) and the roots grow from a rhizome that is like a thick, horizontal stem which is pretty much underground. The roots grow downwards and the fronds grow upwards, but as far as I know from digging up my neighbor's ferns (with permission), both grow out of the rhizome. The fronds start out as cute little fiddleheads that unfurl. (Some are actually edible.) So I don't know what other part of the plant there is. Sorry. I know I'm not helping you. Just doing a biology lesson so might as well add that if you ever see red dots on the back of the fronds, those are called spores and they are the reproductive part of the life cycle. But what are those little boogers that you found? Maybe they are the very tops of the fronds (leaves) and they got sunburned and are falling off or being plucked off by you.
I sure hope someone else jumps into this thread because I'm stumped. In the meantime, I'm going to look at leaves. But don't you pick anymore little martians off the top of the leaves. Maybe they'll do something and that will give us a lightbulb moment.
