Vascular Plants of North Carolina
Section: Common Name: Scientific Name: Family:
Account for Three-leaved Rattlesnake-root - Nabalus trifoliolatus   Cassini
Members of Asteraceae:
Members of Nabalus with account distribution info or public map:
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Section 6 » Family Asteraceae
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AuthorCassini
DistributionMostly Mountains; scattered in the Piedmont and in the Coastal Plain. Range in the Coastal Plain, especially the lower portions, is unclear, and many specimens formerly assigned to N. albus a few decades ago were moved to N. trifoliatus in recent years (Weakley 2024), but Sorrie and LeBlond (2025) indicate that the taxon present in the lower Coastal Plain is part of the N. albus concept and not N. trifoliolatus.

Lab. to Ont., south to GA and TN.
AbundanceInfrequent to fairly common in the Mountains, but generally very rare to rare farther eastward.
HabitatMesic pine-oak-hickory woodlands and forests, openings in the same habitats; forest margins and roadsides.
PhenologyFlowering and fruiting August-October.
IdentificationRattlesnake-roots are characterized by nodding heads of ray florets only, alternate leaves that are roughly triangular and irregularly lobed and/or toothed, and milky juice. Three-leaved Rattlesnake-root grows 2-5 feet tall and has pale yellow or straw-colored pappus (feathery hairs attached to seeds) and pale yellow or cream-colored florets. From N. altissimus it differs in its leaves relatively thick-textured (vs. thin) and greater than 8 florets per head (vs. less than 8). From N. serpentaria it differs in the lack of hairs on the involucre bracts. Also, its lower leaves are palmately 3-5 lobed and with angular lobes and sinuses (vs. pinnately lobed and with rather rounded sinuses and lobes in N. serpentaria). From N. albus it differs by having yellow to cream colored rays vs. white to light pink rays in N. albus.
Taxonomic CommentsThere is much confusion about the Coastal Plain specimens for this species versus N. albus, and these have bounded from one to another in the last 30-50 years. Weakley (2024) included records named as Prenanthes alba ssp. pallida into N. trifoliolatus; all Prenanthes taxa were moved to the genus Nabalus several decades ago.

Other Common Name(s)Gall-of-the-earth
State RankS4? [S4]
Global RankG5
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