Helianthus radula, rayless sunflower

By Jared Barnes

It has been a glorious weekend here in east Texas. For the first time in months our temperature dipped below 70F yesterday, and then Sunday morning, the thermometer registered 59F. I adore days like these where a chill hangs in the air. 

The return of fall and the arrival of cooler temperatures and rain revitalizes the garden. After months of watching plants struggle, it is so nice to see them perking up and many fall performers beginning their show. One species that is becoming a favorite of mine for autumn is rayless sunflower. 

I first saw it on Instagram a few years ago when Andrea England posted a picture of it in a shortgrass prairie in her suburban meadow. At first, I thought I was seeing just spent flowers and seedheads. However, after some sleuthing I realized that this photo was the rayless sunflower in bloom with its black licorice colored disks held on acid green stems. With a brief review of flower morphology, you can see where rayless sunflower gets its name. Many Asteraceae family members have a head inflorescence with two types of flowers, rays that comprised the outer row of colorful “petals” and the inner disks that form the bulk of the flower. The reason the flowers have their orb-like appearance is because they are largely absent of any rays.