Chepiche (porophyllum tagetoides), is related to papaloquelite an aromatic Mexican herb which is normally eaten raw or in tacos or tortas (sandwiches). In Oaxaca it is cooked in a soup called sopa de guias made with squash vines and other herbs. There is no good substitute.
This is an ingredient you'll most likely find in a Mexican produce market. If you live in an area with a large Hispanic population you may find it in your local farmer's market. If you garden you can purchase seeds to grow your own, at Johnny's Seeds. Grow this herb in sun or part shade. Chepiche grows to three to four feet tall.
Can't find chepiche?