Vascular Plants of North Carolina
Account for White Rattlesnake-root - Nabalus albus   (L.) Hooker
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Section 6 » Family Asteraceae
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Author(L.) Hooker
DistributionNorth American species formerly in the genus Prenanthes have now been assigned to the genus Nabalus. Weakley (2018) indicates that records of the old "Prenanthes alba" in the NC Coastal Plain are now assignable to Nabalus trifoliatus; they were formerly named as the subspecies pallida (i.e., named as Prenanthes alba ssp. pallida in RAB [1968]). Therefore, it is the former Prenanthes alba ssp. alba that is now Nabalus albus, as shown on the range map below.

ME to Man., south to NC, WV, MO, and AR.
AbundanceApparently rare, with specimens known from just 6 counties, and reports from 4 others. This is a State Threatened species. The NCNHP's State Rank of S2? might be correct, but the available data suggest a rank of S1S2 is more appropriate. However, because of some taxonomic uncertainties, biologists do not seem to have a good handle on its abundance and distribution.
HabitatMontane forests and woodlands, especially in high pH soils.
PhenologyFlowering and fruiting July-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. White Rattlesnake-root grows 2-5 feet tall and has cinnamon colored pappus (feathery hairs attached to seeds), and white to pale pink florets.
Taxonomic CommentsOuter Coastal Plain plants, formerly Prenanthes alba ssp. pallida, have been re-examined and are now lumped within Nabalus trifoliatus.

Other Common Name(s)Northern Rattlesnake-root, Boott's Rattlesnake-root, White Lettuce
State RankS2? [S1S2]
Global RankG5
State StatusT
US Status
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USACE-empFACU link
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