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CommentsHalberd-Leaved Tearthumb can be distinguished from other similar vines in Illinois by its prickly stems and hastate leaves (shaped like Medieval halberds). Its closest relative in the state, the more common Tracaulon sagittatum (Arrow-Leaved Tearthumb), differs by having sagittate leaves (shaped like arrowheads), ochrea that lack rings of prickles, and seeds that are bluntly 3-angled (rather than biconvex and two-sided). Many contemporary authorities prefer to merge Tearthumb vines (Tracaulon spp.) with the smartweeds (Persicaria spp.). As a result, they refer to Halberd-Leaved Tearthumb as Persicaria arifolia. Another scientific name for this species, Polygonum arifolium, also appears in older sources of information. The classification that is used here follows Mohlenbrock (2002) and Mohlenbrock (2010). The leaves of Halberd-Leaved Tearthumb superficially resemble the leaves of other species, both wild and cultivated, in the Arum family (Araceae). This similarity of form is the source of the scientific name for this species (arifolium).