First off, I know nothing about ferns, so I'm not the best person to answer this question.

However, I've been trying to figure out the ID of a fern of my own today. Yours looks like some of the Doryopteris I've seen. Unfortunately, I don't think we can link to it, because GardenWeb rejects links to the "other" Garden forum (initials: DG). If one looks at their entry for Doryopteris palmata one of their photos looks a lot like your final one.

I just tried linking to that image and Gardenweb forbids it. Try searching for "doryopteris palmata hand fern", without the quotes. The other forum's description comes up as the first answer on a google search.

I just found another which is the same or a related species: Doryopteris pedata. D. palmata is sometimes listed as a variety of this species. I linked to that photo below.

Here is a link that might be useful: {{gwi:608305}}

I wanted to give a link to my post tonight about what may be another member of this genus.

I also wanted to ask a couple questions. Where did you get this plant--which city/county/area was the Trader Joe's in?

I'm also curious if you've checked the position on the fronds where the leaf blades meets the petiole. I've read that Doryopeteris pedata/palmata produces bulbils which then become plantlets. They may or may not be there, and it may depend on factors such as the age of the fronds.

Here is a link that might be useful: ID thread with another possible Doryopteris species