Chickweed. A plant which grows wild near streams and on wasteland and may be eaten raw in salads, cooked in the same way as spinach or used to make soup.
Water chestnut. The corm of a type of a water grass or sedge. They are used in Thai and Chinese cookery to add crunch and are also used to make desserts and drinks elsewhere in South East Asia. They are available fresh or tinned and can be used raw or cooked. They retain their shape well during cooking.