This weedy annual is widespread in warmer American regions, and may have been present in southeastern states before European settlement, perhaps moving north with Zea mays (W; Campitelli & Stinchcombe 2014). The first probable record of hederacea in Ky. was by Rafinesque (1836b, 4:73-75; as "Cleiemera hirsuta"). Some colls. with entire leaves from CARL (MUR), FAYE (KY-Agr.) and elsewhere are referable to the more southern var. integriuscula Gray, but that taxon may not deserve recognition (Cr, Y, W and their citations). There is a cline in leaf shape and several other characters, with Ky. in the transition to more lobed leaves further north (Campitelli & Stinchcombe 2013, Stock et al. 2014); through closer following of air temperature, lobed leaves appear to reduce "radiation frost" during cold nights (Campitelli et al. 2013). A related tropical species, I. nil (L.) Roth, has been erroneously reported from Ky. in some earlier lists (M). Without its distinctive blue flowers with white centers, hederacea can usually be identified from its retrorsely hairy stems and often deeply 3-lobed leaves. Ergoline alkaloids have been found in seeds of hederacea; and some plant extracts also have anti-cancer potential (Meira et al. 2012). Deer and other mammalian herbivores often browse on leaves of hederacea (or other species of Ipomaea), but there is much genetic variation in resistance, and there are potential trade-offs with resistance to insects (Stinchcombe 2002).