Curly dock (Rumex Crispus, also called yellow dock) is one of those plants that is easily overlooked. It doesn’t have a showy flower and the leaves can look kind of generic. Furthermore, it’s not typically as prolific of a weed as a dandelion— at least not in urban areas.
It’s unfortunate that people aren’t more familiar with it, as the leaves, stem, seed, and root are all edible or medicinal. And with its wide distribution, it’s easy to start eating! As a relative of buckwheat, dock seeds are edible as well! Some people say they’re not worth harvesting because so much processing is required to separate the seed from the chaff.
However, you can just grind the seed and chaff all together as one. It’s just extra fibre and won’t hurt you. Seeds appear in late summer and should be harvested when they’re brown, dry, and papery. They often remain on the plant throughout winter.