Vascular Plants of North Carolina
Account for Common Cup-plant - Silphium perfoliatum   L.
Members of Asteraceae:
Members of Silphium with account distribution info or public map:
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Section 6 » Order Asterales » Family Asteraceae
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DistributionMiddle and upper Piedmont and northern Mountains, south only to Ashe and Alleghany counties in the Mountains.

VT to Ont. and ND, south to NC, AL, and TX.
AbundanceRare to locally uncommon, though a few sites have populations of several dozen individuals. The NCNHP database has 30 records, and even though only eight counties have records, the State Rank is clearly S2 and not S1. This is a State Special Concern species.
HabitatFloodplain forests, bottomlands, and openings in same. Typically in openings and edges of alluvial woods and wet thickets, such as along sewerline clearings, and not usually found in pristine habitats.
PhenologyFlowering and fruiting June-August.
IdentificationThis and S. connatum are spectacular and striking species, often reaching 6-9 feet tall, with oddly square (quadrangular) stems in cross-section and numerous fairly large sunflower-like flowers. They differ from other rosinweeds by their paired leaves that are fused basally around the stem (connate). Common Cup-plant has glabrate stems (vs. spreading coarse hairs) and 21-34 ray florets (vs. 8-13 ray florets). If in doubt between these two species, rub the stem; if smooth it is this species but if scabrous, it is S. connatum. Sometimes you can find rainwater forming as pools at the cup-like bases of the leaves of both species.
Taxonomic CommentsMost authors treat Virginia Cup-plant and Common Cup-plant as varieties of S. perfoliatum.

Other Common Name(s)Usually just called Cup-plant, but that covers both this taxon and S. connatum combined. Each needs a modifier name, and Weakley (2018) uses Common Cup-plant for this species.
State RankS1 [S2]
Global RankG5
State StatusSC-V
US Status
USACE-agcpFAC link
USACE-empFAC link
County Map - click on a county to view source of record.
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Katherine HaleNew River State Park AshePhoto_natural
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