Gardengal is correct. It isn't a fern at all but an anemone, which is an ephemeral spring wildflower. The leaves are similar so I can understand your mistake. A very desirable woodland flower, it can make a lovely picture on the woods floor in spring but it completely disappers shortly after blooming, to return next early spring. Maidenhairs don't come up until late April or early May depending on where you live. They have tiny threadlike fiddleheads and wiry black stems, can get to about 2' tall. Sandy

That's a good idea! It's now in a terrarium that I built out of 11x14 inch acrylic panels, sealed with a synthetic epoxy (the top isn't sealed, just saran wrapped). Hopefully after a week it stabilizes and starts to condensate. This is my last resort to keeping this plant alive, so hopefully the maidenhair likes it! I've tried pebble trays, humidifiers, keeping her in the bathroom, etc... These ferns are beautiful but they'll definitely break your heart!

I think this convo spurred me to try again, and I got an Adiantum aleuticum 'Imbricatum', and it apparently likes where I planted it (outside..not a house plant), and still has nearly perfect fronds (mild winter), we shall see. They are lovely...though the challenge for me may be the wetness of early to mid spring for it. The planting location is on the north side of the house, and it gets shaded by a growth of mimulus alatus (winged monkey flower) and it came through summer fantastically. I hope to see spore spread in a year or two, shield fern, lady fern, and painted ferns have performed well for me here and spread along the house foundation area.

Forgot to mention, I'm in NY so it's been pretty cold. It went into the 20s on Friday, which is why I think the heat may help