Vascular Plants of North Carolina
Account for Orangefruit Horse-gentian - Triosteum aurantiacum   Bicknell
Members of Caprifoliaceae:
Members of Triosteum with account distribution info or public map:
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Section 6 » Order Dipsacales » Family Caprifoliaceae
DistributionPresent over nearly all of the Mountains, and sparingly east into the west-central Piedmont.

This is a Northern species ranging from eastern Canada south down the Appalachians to northern GA and to eastern OK.
AbundanceUncommon in the Mountains, but very rare in the Piedmont. This is a Watch List species, though there seem to be enough records and counties to remove the species from such a list.
HabitatThis is a species of rich hardwood forests, always over circumneutral soil, over rocks such as amphibolite. The sites can be somewhat rocky, or mesic and not overly rich, but the soil needs to have a high pH.
PhenologyBlooms mainly from late May to early June, and presumably mid-May to mid-June; fruits from August to October.
IdentificationThis is a robust herb with a hispid stem, often growing to 2.5-3 feet tall. It has numerous pairs of opposite, large stem leaves. Each leaf is widest near the base, and each is ovate to widely lanceolate, entire, 5-6 inches long and 2 inches wide, but is only tapering to the base and not clasping or not strongly clasping (as are the other two species in the genus). In each or most leaf axils are one to several flowers, each tubular and about 1-inch long, generally maroon to purplish in color. The fruit (drupe) is orange and ripens about three months after flowering. The similar T. perfoliatum, to which T. aurantiacum is often lumped as a variety, has strongly clasping leaves so that the stem appears to pass though the pairs of leaves; that species often has pubescent stems but are not strongly hispid. The habitats of these two are quite similar, requiring high pH soils, typically on forested slopes.
Taxonomic CommentsMost references now have these two species as separate species, but many older ones considered this as a variety of T. perfoliatum.

Other Common Name(s)Early Horse-gentian
State RankS2? [S3]
Global RankG5
State StatusW7 [W1]
US Status
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