hairy sunflower

(Helianthus hirsutus)

Conservation Status
hairy sunflower
  IUCN Red List

not listed

     
  NatureServe

N4N5 - Apparently Secure to Secure

SNR - Unranked

     
  Minnesota

not listed

     
           
           
 
Description
 
 

Hairy sunflower is an erect, 24 to 78 tall, perennial forb that rises on usually a single stem from long-creeping, branched rhizomes. The rhizomes do not produce tubers. The plant sometimes forms dense colonies. The overall appearance is of a slender-stemmed, sometimes spindly plant with one or just a few flower heads.

The stems are erect; green, reddish-brown, or tinged with reddish-brown; and unbranched or sparingly branched near the top. They are moderately to densely covered with short, stiff, ascending to spreading hairs. They are sometimes nearly hairless toward the base.

There are usually 8 to 20 leaf nodes below the inflorescence. Lower and middle leaves are opposite, uppermost leaves are usually also opposite, sometimes alternate. Lower and middle leaf blades are narrowly lance-shaped to egg-shaped, relatively thick, and flat, not folded longitudinally. They are 2½ to 7 long and to 2 wide, 2 to 7 times as long as wide, becoming gradually smaller as they ascend the stem. They taper to a sharply pointed tip and may be wedge-shaped, rounded, or squared off at the base. The upper surface is rough to the touch with rough to the touch due to a moderate to dense covering of minute to short, stout hairs. The lower surface is moderately to densely covered with somewhat softer, spreading to loosely appressed hairs, and sparsely to moderately covered with stalkless, yellow glands. The margins are flat and finely toothed to almost untoothed. The leaves have 3 main veins, a prominent midvein and a pair of lateral veins that branch off the midvein at or slightly above the base and arch upward.

The inflorescence is a solitary head or an open cluster of 2 to 7 flower heads at the end of the stem. The flower heads are on stalks that are to 2 long.

The whorl of bracts at the base of the flower head (involucre) is to 1 in diameter. The bracts of the involucre are narrowly lance-shaped to lance-shaped and taper to a sharply pointed tip. The tips of the bracts are loosely ascending to spreading or bent backward.

The flower heads are 1¾ to 3½ wide, the disk is to 1 in diameter. There are 10 to 15 yellow ray florets and 40 or more yellow disk florets.

The fruit is an achene.

 
     
 

Height

 
 

24 to 78

 
     
 

Flower Color

 
 

Yellow ray florets, yellow disk florets

 
     
 

Similar Species

 
 

 

 
     
 
Habitat
 
 

Dry. Woodland edges, meadows, roadsides.

 
     
 
Biology
 
 

Flowering

 
 

July to October

 
     
 

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.

 
     
 
Use
 
 

 

 
     
 
Distribution
 
 

Distribution Map

 

Sources

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

 
  8/18/2014      
         
 

Nativity

 
 

Native

 
         
 

Occurrence

 
 

 

 
         
 
Taxonomy
 
  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  
 

Order

Asterales (sunflowers, bellflowers, fanflowers, and allies)  
 

Family

Asteraceae (sunflowers, daisies, asters, and allies)  
  Subfamily Asteroideae  
  Supertribe Helianthodae  
  Tribe Heliantheae (sunflowers and allies)  
  Subtribe Helianthinae  
  Genus Helianthus (sunflower)  
       
 

Subordinate Taxa

 
 

 

 
       
 

Synonyms

 
 

Helianthus hirsutus var. stenophyllus

Helianthus hirsutus var. trachyphyllus

Helianthus stenophyllus

 
       
 

Common Names

 
 

hairy sunflower

hispid sunflower

oblong sunflower

rough sunflower

stiff-haired sunflower

 
       

 

 

 

 

 

Glossary

Achene

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.

 

Bract

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

 

Involucre

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

 

Node

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

 

Rhizome

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

       
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Colony

  hairy sunflower    
       

Plants

  hairy sunflower   hairy sunflower
       
  hairy sunflower    
       

Inflorescence

  hairy sunflower    
       

Flower Head

  hairy sunflower   hairy sunflower
       

Involucre

  hairy sunflower   hairy sunflower
       

Leaves

  hairy sunflower   hairy sunflower
       
  hairy sunflower   hairy sunflower
       
       

 

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