Apparently monkey puzzle nuts are great, I keep meaning to find some they do seem to seed around here sometimes but they are hard to reach.

I think this might say more about your geographic location than you think :)

People from other continents always surprise me with various fruits they taken for granted their entire life, but I've never heard about, and vice-versa.

Lotus root is pretty common in Chinese and Japanese cuisine. I've had it pickled and in a Sichuan dry pot. It's crunchy and takes on flavors pretty well.

my wife and I regularly eat lotus root, it's quite delicious and common in chinese cooking. the others not so much.

On a side note there are 1000s even 10s of thousand of edible plant based species that grow on the earth. i don't know how old they are though.

Water caltrop nuts are common in Taiwan, very nutty and good for meat soups.

Whoever smelled a ginkgo fruit and said "let's eat this" !

Fiddleheads from ferns are available at farmer's markets in the spring in my area, though not from the cinnamon fern specifically.

I'm having trouble finding sources for other specific fern species, though many ferns have been around for hundreds of millions of years.

Fern fiddleheads aren't bad if you get them at the right time, but I wouldn't go out of my way to eat them.

Lotus root is pretty common. A crunchy tuber that keeps its texture after cooking, bland taste, unique visual appeal. I threw some in the last pot of bean chili my family made, and the kids liked it.