True and False Sunflowers

Oxeye or false sunflowers at Jennings Prairie, August 2013 (photo by Kate St. John)

25 July 2021

At Jennings Prairie Richard Nugent taught me a trick for identifying sunflowers true and false.

Sunflowers are daisy-like composites with a central disc surrounded by ray petals. The disc contains many tiny flowers.

True sunflowers: In true sunflowers, genus Helianthus, the fertile parts are all in the central disc where this bee is feeding. The ray petals are showy but not flowers in their own right.

Tall sunflower with bumblebee, Jennings Prairie (photo by Kate St. John)

It’s easy to find true sunflowers at Jennings Prairie. Tall sunflowers (Helianthus giganteus) towered over our heads.

Tall sunflowers, Jennings Prairie (photo by Kate St. John)

False sunflowers: False sunflowers have fertile rays in addition to the central disc. If you pull off a ray petal you’ll see a tiny pistil at the end where it was attached.

That’s why another name for oxeye sunflower (Heliopsis helianthoides) is false sunflower.

Oxeye or false sunflowers, Jennings Prairie (photo by Kate St. John)

This method is so much easier than deciphering the leaves among Helianthus species.

(photos by Kate St. John)

1 thought on “True and False Sunflowers

  1. Good I information. When done blooming petals stay on oxeye but fall off sunflower leaving just center cone

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