There’s still a lot of commercially produced boysenberry jam out there.
I don’t know if they’ve actually been domesticated, but fiddlehead ferns can be grown in small batches. I’m not aware of any significant commercial operations although they do show up in supermarkets around here. Their range is worldwide but I believe they are native to North America, specifically Canada.
I think ramps fall into a similar category.
Hmm. I did a bit of local poking around. And took wiki’s word for the rest. Although the article was last updated a decade or so ago.
Knott’s still sells the stuff as they did when I was a kid nearby. Although Knott’s is merely a brand name within the Smucker’s jam empire these days. Per Amazon, Smucker’s / Knott’s boysenberry costs about 4x what Smucker’s blackberry costs.
So a specialty product, but yes, cultivated in commercial quantities.
Thanks for showing me the error of my less-than-thorough research. 
I honest to God love boysenberries. Prefer them to any of their relatives among the blackberry/raspberry group. So I will occasionally order boysenberry jam from Amazon for pbj duty .
I miss readily available boysenberry yogurt.
My bad, then - and they’re even more distantly related than I first thought.
I don’t know specifically which species, but there are varieties of beans which are native to North America.
Why is wIld rice’s cultivation not clear? There’s lots of farming for it.
It looks like some theories suggest Chenopodium berlandieri the OG member of its genus, and maybe others, most notably the domesticated quinoa, is from it. Others dispute that. The parent species doesn’t have a commercial market that I’m aware of, but it’s popular among foragers (perhaps more commonly known as lamb’s quarters than goosefoot).
Marionberry is just a blackberry cultivar, but don’t tell Oregonians that, they pretend like it’s some completely unique thing.
Ramps in Switzerland is known as Bear’s Garlic (Allium ursinum). Which is in the same Genus as ramps (Allium tricoccum).
Probably not often grown as a domesticated crop, but devil’s club can be planted and is is used as a tea and medicine.
It also would be removed in your OP as a whole-of-geographic-North-America crop and having been in precolumbian cultivation in the Antilles and Mexico.
I second this. It’s right there on their flag.
How about poke/pokeweed?
Not a common crop, but until the early 00’s there were a couple companies that provided it canned.
Boysenberries are hybrids of raspberry/blackberry species from Europe - the cross-breeding may have happened in the USA, but the OP specifies:
(emphasis mine)
The Hood® Dairy considered making a boysenberry flavored milk. Guess what it was going to be called…
“Boys in the Hood” / “Boysen the Hood” ?