I believe the ones with all smooth edges are broccoli. I don't have labelled ones, but I don't neet to.

Just to complicate things, broccoli I've grown has 'wiggly' leaves, rather than serrated, while collards are always smooth.

LOL! It's the smaller, new, inner leaves that are different. The outer leaves are identical. Anyone?

The leaves of my broccoli seedlings have more-serrated edges and are more elongated than my collards. The collards are rounder and have smoother edges.

To be honest I can't tell the differnce when they are young. On the positive side, they are similar size plants with very similar growing requirements so you can interplant them with no problem.
Collard {{gwi:112997}}
Broccoli {{gwi:50461}}

Thanks to each one of you. I found a picture of Champion Collards (the type I planted) on the web that I believe showed the inner leaves with serrated edges. But with the conflicting information from all of you, I guess I'll have to wait until the broccoli heads up to know for certain. Anybody ever eat broccoli leaves?? Thanks again for responding, and I mean that from the bottom of my heart. Now you all have my permission to have a good laugh at such a rookie mistake from someone with 25 years of gardening experience; though only 2 with collards and none with broccoli. Who knew?

Post pictures and we may be able to guess. Otherwise, you'll find out soon enough!

Broccoli leaves taste pretty good. Like mild kale. Kind of like ... collards.

Donnabaskets,
In 1983 I decided to grow collards on a larger scale, enough for a few of my friends and myself to have a big mess for turkey day and Christmas. Wellllllllllllllll we had a little party and everyone took home enough collards for there familys turkey day, every one including myself thought they were the best collards ever. The darnest thing tho 3-4 weeks later every plant started growing the strangest growth out of the center, Yep I had 60 heads of broc to eat and give away. Young broc plants are every bit as good as collards. Now I add broc leafs to the collards because I like em. Try it, its good if you eat them while there still young.
Plant em if you got em.
Sam

How about that? This story just gets better and better!