KNP Rare Plants Database


 
KY Office of Kentucky Nature Preserves




Silphium Sunflower
Helianthus silphioides
Family: Asteraceae

Protection Status:
State Status:  E
USFWS Status: 

Global Rank: G3G4
State Rank: S1

   

Photo by Dennis D. Horn @ TENN
Habitat:
Low sandy alluvial soils, fallow fields, woodland borders, open dry uplands, thickets and roadsides.

Species Description:
Perennial herb.

Phenology:
Flowering Period: Early July to late October.

Additional Information at NatureServe

Diagnostic Characteristics:
This sunflower can be distinguished by the ovate to suborbicular leaves that abruptly contract to a winged petiole. The leaves are gradually reduced in size toward the top of the stem (these are abruptly contracted in H.atrorubens). These are mostly distributed on the lower half of the plant. The disc portion of the flower is red-purple.

Management:
Disturbance such as ATV trails, timber removal or any activity that results in increased erosion and weed invasion will be detrimental.

Global Range:
H. silphioides occurs from Alabama west to Louisiana, and north to western Kentucky, southern Illinois, and southeastern Missouri. May be extirpated from Illinois (Vlaszek 1995).

Known Kentucky Occurrences:
Species occurrence map

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Data Last Updated: November 2018
Office of Kentucky Nature Preserves
300 Sower Blvd
Frankfort,KY 40601
Phone: (502) 573-2886
Email:
naturepreserves@ky.gov
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