Vascular Plants of North Carolina
Account for Pipevine - Isotrema macrophyllum   (Lamarck) C.F. Reed
Members of Aristolochiaceae:
Members of Isotrema with account distribution info or public map:
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Section 4 » Family Aristolochiaceae
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Author(Lamarck) C.F. Reed
DistributionThroughout the mountains. Apparently no records from the Piedmont, except as escapes. Certainly present in all mountain counties.

This is a Northern species found from southeastern Canada and ME south, mainly in the Appalachians, to northwestern SC, northern GA, and eastern TN.
AbundanceFairly common to locally common over the mountains. In some ranges with much high pH soils, it can be a very common woody species. Least numerous in the far southwestern counties.
HabitatThis is a classic Rich Cove Forest species, being found primarily on rich wooded slopes. It can be found on higher and drier slopes and ridges, but primarily where mafic rocks, such as amphibolite, underlie the site.
See also Habitat Account for Rich Montane Hardwood Forests
PhenologyBlooms in May and June; fruits in August and September.
IdentificationThis is a very distinctive, high-climbing, deciduous woody vine. It has alternate, very large cordate leaves, with entire margins; length averages about 6 inches across and long. The namesake flowers are on stalks several inches long, being greenish to brown-maroon, and pipe-shaped, often 2 inches long. The flowers are followed by ribbed, cylindrical capsules to 2-3 inches long. Hardly anyone will need flowers or capsules to identify this species, especially as, where it occurs, it can sprawl over other vegetation or climb tens of feet into the higher canopy trees. In some cove forests, it may be the most obvious plant. As the common name of the butterfly implies, this is the main native hostplant for the Pipevine Swallowtail.
Taxonomic CommentsSeveral recent references have placed this species in another genus, as Isotrema macrophyllum. Older references had the species named as Aristolochia durior and also as A. macrophylla.

Other Common Name(s)Dutchman’s-pipe
State RankS4
Global RankG5
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