Boston-ivy, P. tricuspidata (Siebold & Zucc.) Planch., a native of Asia, is very commonly cultivated but as yet does not seem to escape in our area; at most stray seedlings have been observed in cultivated areas near planted specimens. It has simple, 3-lobed, maple-like leaves, except on basal shoots, where they may be trifoliolate.
Our two native species are not always easy to tell apart, especially from herbarium specimens that lack well-developed tendrils, mature inflorescences, or notes on the label as to appearance of the fresh leaflets and tendrils. Both species are cultivated, P. quinquefolia preferred for climbing walls (as well as trees). Unlike Vitis, the fruits are not recommended for eating, although a reputation for being poisonous may be exaggerated.
1. Leaflets ± shiny above when fresh, at most slightly paler beneath but not whitened; tendrils not developing adhesive discs (though sometimes club-shaped at the ends when in a crevice); inflorescence branches equal in size and thickness, the inflorscence thus equally forking (dichotomous -- or occasionally trichotomous) throughout, and lacking a central axis.
1. Leaflets dull above when fresh, pale green and whitened or slightly glaucous beneath; tendrils with each branch forming an adhesive disc at the end if it comes in contact with a support; inflorescence branches clearly unequal, the inflorescence thus with a definite zig-zag central axis.
All species found in Parthenocissus
MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. December 7, 2021. https://michiganflora.net/genus.aspx?id=Parthenocissus.