What type of greens are these? It looks like a leafy green and it has a purple stalk.

I got some greens at the farmer’s market donated for an event we are attending. I want to know what type of green they are. They have green leaves with a purple stalk. The edges of the green leaves are not rounded like spinach. Thank You.

P.S. I tried to google but with no results. I tried both regular and image search.