I had always thought that was "polk salad" as in the Elvis song Polk Salad Annie.Collards are a loose leafy vegetable that is in the same family of brassicas as kale, spring greens, cabbage, broccoli, etc. Brassicas are actually in the mustard family of plants, and are sometimes known as cole crops, from the Latin "caulis" for the stem of the plants, that designation being from whence coleslaw gets its name.
I tend mix my greens when cooking them up. My typical collard greens will include collards, mustard greens, and poke sallet, often with a bit of spinach thrown in as well. Also, fairly traditional when cooking down your greens to throw in a nice ham hock, or some pork belly. Poke sallet is not a brassica, it is a phytolacca, and poisonous to mammals, but great for attracting birds. You have to pick poke sallet early in the spring, and prepare it properly not to off yourself.
I think the various types of cabbage tend to be under-rated in the scoff stakes. I imagine mostly because of the way the poor little things were cooked by our female forebears,, schools, the armed forces and various other institutions. Boiled for nine hours.
I only found out cabbage was green in my early twenties. Thanks for all the grey slop Mum.