Helianthus radula

From Coastal Plain Plants Wiki
Jump to: navigation, search
Helianthus radula
Helianthus radula.jpg
Photo was taken by Gil Nelson
Scientific classification
Kingdom: Plantae
Division: Magnoliophyta - Flowering plants
Class: Magnoliopsida – Dicotyledons
Order: Asterales
Family: Asteraceae ⁄ Compositae
Genus: Helianthus
Species: H. radula
Binomial name
Helianthus radula
(Pursh) Torr. & A. Gray
HELI RADU dist.jpg
Natural range of Helianthus radula from USDA NRCS Plants Database.

Common names: rayless sunflower; stiff sunflower; roundleaf sunflower

Taxonomic notes

Synonyms: none[1]

Varieties: none[1]


A description of Helianthus radula is provided in The Flora of North America.

Helianthus radula is a perennial herbaceous species. It is very distinguishable by its rosette of orbicular and nearly round leaves, which are borne basally to the ground.[1]


Helianthus radula is found along the southeastern coastal plain from southern South Carolina south to southern peninsular Florida and west to southeastern Louisiana.[1]



Generally, H. radula can be found in dryish savannas and sandhills as well as dry pine flatwoods.[1] It can live in loblolly or slash pine communities,[2] upland longleaf pine communities, [3][4] pine-oak sandhill woodlands, near the edges of bogs, limestone glades, and mixed oak-cabbage palm hammocks. Additionally, it occurs in disturbed areas such as roadsides, old fields, power line corridors, by trails, and in lawn and waste areas. This species seems to prefer semi-shaded areas, and occurs on mostly wet to dry sandy soils, or over limestone.[5] As well, it is considered an indicator species of the Florida panhandle silty longleaf woodlands habitat.[6] A study exploring longleaf pine patch dynamics found H. radula to be most strongly represented within longleaf pine gaps and under patches of longleaf that are up to 50 years of age.[7]

H. radula is very vulnerable to disturbance, which could be due to its method of seed dispersal.[8] H. radula was found to become absent in response to soil disturbance by agriculture in southwest Georgia. It has shown resistance to regrowth in reestablished savanna habitat that was disturbed by agricultural practices.[8]

Associated species include Pinus palutris, Quercus laevis, Serenoa repens, Sabatia brevifolia, Kalmia hirsuta, Balduina uniflora, Polygala lutea, Sorghastrum secundum, Quercus pumila, Seymeria cassioides, Liatris graminifolia, Helianthus heterophyllus, Cirsium, Bigelowia, Ludwigia, Pinus elliottii, Pityopsis, Baptisia simplicifolia, Ilex glabra, Andropogon, Rynchospora, Phoebanthus tenuifolia, Eupatorium album, Pityopsis, Rhexia alifanus, Liatris gracilis, Carphephorus odoratissimus, Baptisia simplicifolia, Ctenium aromaticum, Vaccinium darrowi, Quercus pumila, Quercus minima, Gaylussacia dumosa, and Physostegia godfreyi.[5]


This species generally flowers from late August until October.[1] Flowering and fruiting has been observed in January and August through November.[5][9]

Seed dispersal

This species is thought to be dispersed by gravity. [10]

Fire ecology

This species has been found in habitat that is burned frequently,[5] even biennially.[4]

Herbivory and toxicology

The stem and leaves of this species were found to be eaten by white-tailed deer during the fall and winter[11], and is an attractive nectar plant for butterflies.[12]

Conservation, cultivation, and restoration

H. radula should avoid soil disturbance by agriculture to conserve its presence in pine communities.[8] Due to its restricted habitat within its small range, Helianthus radula is listed as G4 on the global scale.[13]

Cultural use

Photo Gallery

References and notes

  1. 1.0 1.1 1.2 1.3 1.4 1.5 Weakley, A.S. 2020. Flora of the Southeastern United States. Edition of 20 October 2020. University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
  2. Yager, L. Y., M. G. Hinderliter, et al. (2007). "Gopher tortoise response to habitat management by prescribed burning." The Journal of Wildlife Management 71: 428-434.
  3. Kirkman, L. K., M. B. Drew, et al. (1998). "Effects of experimental fire regimes on the population dynamics of Schwalbea americana L." Plant Ecology 137: 115-137.
  4. 4.0 4.1 Gilliam, F. S., W. J. Platt, et al. (2006). "Natural disturbances and the physiognomy of pine savannas: A phenomenological model." Applied Vegetation Science 9: 83-96.
  5. 5.0 5.1 5.2 5.3 Florida State University Robert K. Godfrey Herbarium database. URL: http://herbarium.bio.fsu.edu. Last accessed: June 2014. Collectors: Loran C. Anderson, Roomie Wilson, Delzie Demaree, C. Ritchie Bell, F. H. Sargent, Samuel B. Jones, John W. Thieret, Almut G. Jones, A. F. Clewell, R. K. Godfrey, Bruce Hansen, JoAnn Hansen, Robert L. Lazor, R. Kral, J. P. Gillespie, R. E. Perdue, Jr., Paul L. Redfearn, Jr., Kurt E. Blum, D. B. Ward, S. S. Ward, John B. Nelson, G. R. Knight, Cecil R Slaughter, Nancy E. Jordan, R. A. Norris, and R. Komarek. States and Counties: Florida: Bay, Calhoun, Citrus, Flagler, Franklin, Gadsden, Holmes, Jefferson, Lake, Leon, Levy, Liberty, Madison, Nassau, Okaloosa, Orange, Osceola, Putnam, St Johns, Taylor, Wakulla, and Walton. Georgia: Thomas. Louisiana: Tangipahoa and Washington. Mississippi: Jackson, Lamar, and Pearl River. South Carolina: Colleton.
  6. Carr, S. C., et al. (2010). "A Vegetation Classification of Fire-Dependent Pinelands of Florida." Castanea 75(2): 153-189.
  7. Mugnani et al. (2019). “Longleaf Pine Patch Dynamics Influence Ground-Layer Vegetation in Old-Growth Pine Savanna”.
  8. 8.0 8.1 8.2 Kirkman, L. K., et al. (2004). "Ground Cover Recovery Patterns and Life-History Traits: Implications for Restoration Obstacles and Opportunities in a Species-Rich Savanna." Journal of Ecology 92(3): 409-421.
  9. Nelson, G. PanFlora: Plant data for the eastern United States with emphasis on the Southeastern Coastal Plains, Florida, and the Florida Panhandle. www.gilnelson.com/PanFlora/ Accessed: 12 DEC 2016
  10. Kirkman, L. Katherine. Unpublished database of seed dispersal mode of plants found in Coastal Plain longleaf pine-grasslands of the Jones Ecological Research Center, Georgia.
  11. Harlow, R. F. (1961). "Fall and winter foods of Florida white-tailed deer." The Quarterly Journal of the Florida Academy of Sciences 24(1): 19-38.
  12. Denhof, Carol. 2015. Plant Spotlight Rayless Sunflower Helianthus Radula (Pursh) Torr. & A. Gray. The Longleaf Leader – Old Growth Forest The Legacy of Longleaf. Vol. VIII. Iss. 3. Page 14
  13. [[1]] NatureServe Explorer. Accessed: May 22, 2019