marigold (Tagetes erecta) (see Karttunen); also called the "dianthus of the Indies" (see Hernández)
See an image that represents cempohualxochitl in the Visual Lexicon of Aztec Hieroglyphs, ed. Stephanie Wood (Eugene, Ore.: Wired Humanities, 2020-present).
"Seven major varieties of this herb are found in New Spain . . . all of which have tough leaves, yellow or pale-colored flowers . . . It expels wind, excites sexual appetite, and . . . it is an admirable remedy for all cold ailments, evacuating the cause of the illness by means of urination and sweating . . . when it has coagulated with a little wax, it is a most famous cure for wounds and hermorrhoids."