stiff sunflower

(Helianthus pauciflorus ssp. pauciflorus)

Conservation Status


No image available

  IUCN Red List

not listed


N5? - Secure

SNR - Unranked


not listed


Stiff sunflower (ssp.pauciflorus) is an erect, annual forb that rises on a single stem from long, thick, branched, creeping rhizomes. It can be from 32 to 78 tall, though it is usually no more than 60 in height. It often forms colonies.

The stems are erect, green or reddish-brown, and unbranched or sparingly branched near the top. They are rough to the touch due to a moderate to dense covering of short, stiff, ascending to spreading hairs. The stems are usually leafless near the top.

There are usually 8 to 15 leaf nodes below the inflorescence. Lower leaves are opposite, uppermost leaves are usually alternate. Lower and middle leaves are oblong lance-shaped to narrowly egg-shaped, relatively thick, and flat, not folded longitudinally. They are 3 to 10 long and ¾ to 2 wide, 2½ to 8 times as long as wide. They are wedge-shaped at the base and taper gradually to a sharp point at the tip with concave sides along the tip. The upper and lower surfaces are rough to the touch due to a moderate to dense covering of minute, stiff hairs. They are also sparsely to moderately covered with minute, stalkless, yellow glands. The margins are finely toothed to almost untoothed. The leaves have 3 main veins, a midvein and a pair of lateral veins that branch off the main vein well above the base and arch upward.

The inflorescence is sometimes a solitary head, usually an open cluster of 2 to 10 flower heads at the end of the stem. The flower heads are on stalks that are 13 16 to 4¾ long.

The whorl of bracts at the base of the flower head (involucre) is to in diameter. The bracts of the involucre are elliptic to egg-shaped and taper to a blunt or sharp point at the tip. The tips of the bracts are tightly appressed.

The flower heads are 1½ to 2½ wide, the disk is to 1 in diameter. There are 10 to 20 yellow ray florets and 75 or more reddish-brown to purple disk florets.

The fruit is an achene.




32 to 60


Flower Color


Yellow ray florets, reddish-brown to purple disk florets


Similar Species


Stiff sunflower (Helianthus pauciflorus ssp. subrhomboideus) tends to be shorter, 12 to 48 in height. There are usually only 5 to 10 leaf nodes below the inflorescence. The uppermost leaves are usually opposite. The lower and middle leaves are shorter, 2 to 4¾ long. They are rhombic egg-shaped to lance-linear and taper to a blunt or sharp point at the tip with straight sides along the tip.


Dry to moderately wet. Prairies, upland forest openings, pastures, railroads, roadsides.




July to September


Pests and Diseases


Sunflower bullet gall midge (Pilodiplosis helianthibulla) makes ¼ in diameter, almost globe-shaped galls on the leaves of plants in the genus Helianthus.


Defense Mechanisms


The roots exude chemicals that inhibit seed germination and growth of young plants. When in a dense colony, these chemicals may cause the inner plants to die, leaving a ring of living plants.




Distribution Map



3, 4, 7, 28, 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 Helianthinae  
  Genus Helianthus (sunflowers)  
  Species Helianthus pauciflorus (stiff sunflower)  

The species name pauciflorus means few-flowered.




Subordinate Taxa






Helianthus laetiflorus var. rigidus

Helianthus rigidus


Common Names


few-leaved sunflower

prairie sunflower

stiff sunflower









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 entirely from the wall of the superior ovary, does not split open at maturity, but relies on decay or predation to release the contents.



The release of a chemical toxin by one plant to inhibit the growth or germination of nearby competing plants.



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



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



Long, straight, and narrow, with more or less parallel sides, like a blade of grass.



The small swelling of the stem from which one or more leaves, branches, or buds originate.



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

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