Plants of Concern staff and volunteers monitor many threatened, endangered, and rare vascular plants in Illinois. A species in the latter category which has become a recent monitoring priority in our Northwestern and Southern regions is the Midwest rose turtlehead (Chelone speciosa). This charismatic wildflower of floodplains was recently elevated from variety to species status, thus adding it to the list of vascular plant species endemic to the Midwest!

From Variety to Species

Chelone speciosa belongs to the rose turtlehead (Chelone obliqua) complex and was formerly known as Chelone obliqua var. speciosa. Nelson (2024) concluded that morphological, genetic, and geographic differences within the complex warrant recognition of three distinct species: Chelone erwiniae, Chelone obliqua, and Chelone speciosa. Specifically, Nelson (2024) found meaningful differences in the degree of hairiness on sepal margins and mid-stem leaf dimensions.

Sepal ciliation (hairiness on sepal margin) of Chelone speciosa. Photo by Grant Fessler.

In addition, previous work on the genetics of the complex suggested that each entity originated independently from each other. Nelson (2024) found that these morphological and genetic differences sort geographically, with each entity occupying a distinct ecoregion. Chelone erwiniae is found in the Blue Ridge Mountains and adjacent highlands, Chelone obliqua is found in the Atlantic Coastal Plain, and Chelone speciosa is found in the Central lowland of the Midwest (Nelson 2024).

A Species at Risk

As of October 2025, NatureServe cites Chelone obliqua var. speciosa (Chelone speciosa) as known from 8 states and ranked as globally vulnerable (T3). It is currently extant in 6 states: Illinois, Indiana, Iowa, Kentucky, Michigan, and Missouri (NatureServe 2025). Native populations are historical in Arkansas and Minnesota (Nature Serve 2025). It is critically imperiled (S1) in Michigan, and vulnerable (S3) in Illinois, Indiana, and Kentucky (NatureServe 2025). It is currently unranked in the other states in which it is extant. Threats to Chelone speciosa include habitat destruction, hydrological changes to its habitat, intense long-duration flooding and siltation, and closure of floodplain forest canopies (NatureServe).

County-level range map of the Chelone obliqua complex courtesy of BONAP.org.

Monitoring Illinois Populations

Plants of Concern tracks this species in our Northwestern and Southern regions where it is native to open floodplain forests and riverbanks of the Mississippi River and its tributaries. In Northeastern Illinois, however, this species is not monitored since Wilhelm and Rericha (2017) consider it introduced to the Chicago region. Monitoring data of Illinois occurrences show that most populations are small (fewer than 100 stems) and are relatively distant from each other. These conditions may put the species at risk of decline.

The continued monitoring by Plants of Concern of this striking wildflower will help to inform its long-term status in Illinois. Click here to read the full article by Nelson on the Taxonomy of the Chelone obliqua (Plantaginaceae) Polyploid Complex! Also check out this video to watch pollination of Chelone speciosa in action! 

Common eastern bumble bee (Bombus impatiens) emerging from Chelone speciosa. Photo by Grant Fessler.

Written by Grant Fessler, Northwestern Region Coordinator

References

Iowa Department of Natural Resources. N.d. Endangered, threatened, and special concern plants. https://www.legis.iowa.gov/docs/ACO/rule/571.77.3.pdf

Michigan Department of Natural Resources. 2023. Threatened and endangered species list. https://www.michigan.gov/dnr/managing-resources/wildlife/wildlife-permits/threatened-endangered-species/threatened-and-endangered-species-list

Mohlenbrock, R.H. 2014. Vascular Flora of Illinois: A Field Guide, 4th edition. Southern Illinois Univ. Press, Carbondale.

NatureServe. 2025. Chelone obliqua var. speciosa - Rose Turtlehead. NatureServe Explorer. NatureServe, Arlington, Virginia. Available at https://explorer.natureserve.org/Taxon/ELEMENT_GLOBAL.2.150679/Chelone_obliqua_var_speciosa

Nelson, A. 2024. Taxonomy of the Chelone obliqua (Plantaginaceae) polyploid complex. Phytoneuron 2024-80: 1–8. Published 18 December 2024. ISSN 2153 733X. https://www.phytoneuron.net/wp-content/uploads/2024/12/80PhytoN-CheloneobliquaComplex.pdf

Office of Kentucky Nature Preserves. 2019. Endangered, Threatened, and Special Concern Plants, Animals, and Natural Communities of Kentucky. https://eec.ky.gov/Nature-Preserves/biodiversity/Documents/Rare_species_of_Kentucky.pdf