Guasca (or guascas) Galinsoga parviflora, also known as piojito (in Oaxaca), pacpa yuyo, burrionera, gallant soldier and potato weed, is an herb native to South America.
In Colombia it is used as a herb in the soup ajiaco. In Oaxaca, it is used as an ingredient in sopa de guías, a soup made from squash vines, fresh corn and wild herbs. It can also be used as an ingredient in leaf salads, although its subtle flavor, reminiscent of artichoke, mostly develops after being cooked.