I bought a bunch of cilantro today. Some of these leaves were mixed in with the cilantro. What are they? Are they edible?
Don't consume unknown plants for safety reasons, not even ones identified by a random stranger on the internet!
It is very difficult to identify plants based just on leaves alone, generally for a certain identification you need stems, flowers and/or seeds to be absolutely certain
Having said that:
These look very much like young Mallow leaves (Malva from the Malvaceae), which is a genus of widespread plants found in temperate to tropical areas. Many species are considered weeds and are common in disturbed soils in urban areas.
The things that make me think it is mallow are the kidney-shaped leaves, with indented teeth and a dark spot where the petiole meets the blade
Most of the species of Mallow are edible, with a pleasant sweet taste to them. Some of the species are common garden flowers - usually a pretty pink or sometimes white.
This also looks like Centella asiatica or Indian pennywort, which is used as a culinary vegetable and as a medicinal herb.
It depends on what type of cilantro you bought. If you bought confetti cilantro, the leaves would look much more thin, and have a touch of lime taste to it. If you did buy confetti cilantro, I’d recommend throwing out the odd leaves, because they wouldn’t mistake a plant that different. If you bought leaf cilantro, which looks very similar to the one in the picture, try smelling it to make sure it smells like cilantro.