Echinacea purpurea (L.) Moench
| A revision of the bees of the genus Melissodes in North and Central America. Part III (Hymenoptera, Apidae) (1961) University of Kansas Science Bulletin 42: 283-663 | |
| The modern names for Catesby's plants R A Howard and G W Staples (1983) Journal of the Arnold Arboretum 64: 511-546 |