cup plant

(Silphium perfoliatum var. perfoliatum)

Conservation Status
cup plant
  IUCN Red List

not listed


NNR - Unranked

SNR - Unranked


not listed

Wetland Indicator Status
  Great Plains

FAC - Facultative


FACW - Facultative wetland

  Northcentral & Northeast

FACW - Facultative wetland


Cup plant is an erect, perennial forb that rises on usually a cluster of several stems, sometimes a single stem, from a central taproot; numerous shallow, spreading rhizomes; and fibrous roots. It can be 2½ to 10 in height, but is usually no more than 8 tall. It sometimes forms colonies.

The stems are erect, stout, square in cross section, unbranched below the inflorescence, and usually hairless. They are often shiny with a varnished appearance. They are occasionally slightly covered with a whitish, waxy coating (glaucous). They are green at first, often becoming reddish as the season progresses.

Basal leaves are egg-shaped to triangular egg-shaped or lance-shaped, unlobed, long-stalked, 4 to 12 long, and up to 9½ wide. They are rough to the touch and thick but not leathery or only slightly leathery. The leaf stalk is often expanded at the base into an ear-like lobe that wraps around the stem. The leaf blade is tapered or angled at the base and tapers to a sharp point at the tip. The margins are coarsely toothed.

Stem leaves are opposite, 1¼ to 13¾ long, and ¼ to 9½ wide. The bases of opposite leaves are fused together at the base (perfoliate) to form a cup that holds water. Stem leaves are otherwise similar to basal leaves. They become progressively smaller as they ascend the stem from near the midpoint. Basal and lower stem leaves are withered or absent at flowering time.

The inflorescence is a loose, open, branched cluster (panicle) of several flower heads at the end of the stem. The flower heads may be long- or short-stalked or unstalked.

The flower heads are 1¾ to 2¾ in diameter. The whorl of modified leaves (bracts) at the base of the flower head (involucre) is bell-shaped to hemispheric and ½ to 1 long. It is composed of 25 to 37 bracts (phyllaries) in 2 or 3 overlapping series. The phyllaries are elliptic to broadly egg-shaped, pointed at the tip, usually hairless, and ½ to 11 16 long. The outer series is tightly appressed.

There are 17 to 35 ray florets and 85 to 150 or more disk florets. The ray florets are yellow and to 19 16 long. The disk florets are yellow.

The fruit is a dry, one-seeded seed capsule (cypsela). The cypsela is black to brown, egg-shaped, flattened, 5 16 to ½ long, and 3 16 to wide. It is broadly winged and has a deep notch at the tip. There is no tuft of hairs attached to the end.




30 to 120


Flower Color


Yellow ray florets, yellow disk florets


Similar Species




Wet to moderate moisture. Prairies, meadows, fens, woodland edges, streambanks, and ditches. Full or partial sun.




July to September


Pests and Diseases






Distribution Map



2, 3, 4, 5, 7, 28, 29, 30.









  Kingdom Plantae (green algae and land plants)  
  Subkingdom Viridiplantae (green plants)  
  Infrakingdom Streptophyta (land plants and green algae)  
  Superdivision Embryophyta (land plants)  
  Division Tracheophyta (vascular plants)  
  Subdivision Spermatophytina (seed plants)  
  Class Magnoliopsida (flowering plants)  
  Superorder Asteranae  


Asterales (sunflowers, bellflowers, fanflowers, and allies)  


Asteraceae (sunflowers, daisies, asters, and allies)  
  Subfamily Asteroideae  
  Supertribe Helianthodae  
  Tribe Heliantheae (sunflowers and allies)  
  Subtribe Engelmanniinae  
  Genus Silphium (rosinweeds)  
  Species Silphium perfoliatum (cup plant)  

Subordinate Taxa






Common Names


cup plant



cupleaf rosinweed

squarestem rosinweed












Modified leaf at the base of a flower stalk, flower cluster, or inflorescence.



A dry, one-chambered, single-seeded fruit, formed from a single carpel, with the seed attached to the membranous outer layer (wall) only by the seed stalk; the wall, formed from the wall of the inferior ovary and also from other tissues derived from the receptacle or hypanthium, does not split open at maturity, but relies on decay or predation to release the contents.



Pale green or bluish gray due to a whitish, powdery or waxy film, as on a plum or a grape.



A whorl of bracts beneath or surrounding a flower or flower cluster.



A pyramidal inflorescence with a main stem and branches. Flowers on the lower, longer branches mature earlier than those on the shorter, upper ones.



A leaf having margins that entirely surround the stem, giving the appearance that the stem is growing through the leaf.



An individual bract within the involucre of a plant in the Asteraceae family.



A horizontal, usually underground stem. It serves as a reproductive structure, producing roots below and shoots above at the nodes.



A thin, flat, membranous, usually transparent appendage on the margin of a structure.

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Flower Head

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Early Spring

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Other Videos
  Cup Plant - Silphium perfoliatum at Ion Exchange

Uploaded on Aug 1, 2011

Earthyman films Cup Plant (Silphium perfoliatum) growing at Ion Exchange in NE iowa. Bright yellow flowers bloom in July/August.

  Minnesota Native Plant - Cup Plant (Silphium Perfoliatum)

Published on Aug 8, 2013

Todays plant is the Cup Plant (Silphium Perfoliatum var. Perfoliatum). A beautiful plant to have near a pond!




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