Collard refers to certain loose-leafed cultivars of Brassica oleracea, the same species as many common vegetables, including cabbage and broccoli. Collard is a member of the Viridis Group of Brassica oleracea. Wikipedia
Collard greens are a staple vegetable in Southern U.S. cuisine. They are often prepared with other similar green leaf vegetables, such as spinach, kale, turnip greens, and mustard greens in the dish called “mixed greens“. Typically used in combination with collard greens are smoked and salted meats (ham hocks, smoked turkey drumsticks, smoked turkey necks, pork neckbones, fatback or other fatty meat), diced onions, vinegar, salt, and black pepper, white pepper, or crushed red pepper, and some cooks add a small amount of sugar. Traditionally, collards are eaten on New Year’s Day, along with black-eyed peas or field peas and cornbread, to ensure wealth in the coming year. Cornbread is used to soak up the “pot liquor“, a nutrient-rich collard broth. Collard greens may also be thinly sliced and fermented to make a collard sauerkrautthat is often cooked with flat dumplings. Landrace collard in-situgenetic diversity and ethnobotany are subjects of research for citizen-science groups.