CPC National Collection Plant Profile

Physostegia correllii

Douglas K. Williams

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CPC National Collection Plant Profile

Physostegia correllii

Common Name: 
Correll's false dragon-head
(Lundell) Shinners
Growth Habit: 
CPC Number: 


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 Fish & WildLife

Physostegia correlliienlarge
Photographer: Douglas K. Williams
Image Owner: Mercer Arboretum and Botanic Gardens

Physostegia correlliienlarge
Photographer: Douglas K. Williams
Image Owner: Mercer Arboretum and Botanic Gardens

Physostegia correllii is Not Sponsored
Primary custodian for this plant in the CPC National Collection of Endangered Plants is: 
Dave Berkshire contributed to this Plant Profile.

Physostegia correllii

Correll's false dragonhead is an endangered, water-loving perennial that once occurred in several areas in Texas, Louisiana, and Mexico but is now restricted to two or three sites in Louisiana and one possible site in Travis County, Texas (Poole 2001; Singhurst 2001). Its current status in Coahuila, Nuevo Leon and Sonora, Mexico is unknown.

Physostegia correllii bears lavender snapdragon-like flowers in July on tall slender stalks that can reach seven feet. This species is considered the center of origin for the entire Physostegia genus in southeastern Texas and western Louisiana. Because of this, and because it contains a complex of traits found in other Physostegia, it may prove useful for understanding the evolution of the genus.

Distribution & Occurrence

State Range
State Range of  Physostegia correllii
  Historically these plants occurred in wetland habitats of the Gulf Coastal region of TX and LA and inland into TX and Mexico (Irving 1980). The remaining populations occur in many diverse, unstable wetland habitats: stream sides, roadside ditches and irrigation canals.

Physostegia is often found associated with Johnson Grass (Sorghum), Spike Rush (Eleocharis spp.), Alligatorweed (Alternanthera philoxeroides) and Cottonwood (Populus spp) (Irving 1980).

  P. correllii populations had been reported in Galveston, Montgomery (H), Bexar (H), Travis, Val Verde, and Zapata counties in Texas, as well as in Nuevo Leon, Coahila, Sonora in Mexico and Cameron, St. Charles, St. James and St. Tammany Parishes in Louisiana (Poole et al. 2002; Faulkner 2001). One possible population occurs in Travis County, TX and 2-3 possible in LA (Poole 2001; Singhurst 2001; Faulkner 1999). The status of the Mexican populations is unknown.

Number Left
  Of the 8 historical sites in TX, LA and Mexico, an unknown number of individuals remain. An unknown number of individuals remain in 2-3 unprotected sites in LA. One site in Travis County, TX is being confirmed (Singhurst 2001). Its current status in Mexico is unknown.
LA Natural Heritage Program reports (Faulkner 1999):
from 4 sites in LA:
Site 1 – St. Charles Parish; presumed extirpated from this site; last observation 1975, no plants found during resurvey in 1986.
Site 2 – in Cameron Parish; last observation 1990 with 40 stems counted; flowers in mid-July.
Site 3 – St. Tammany Parish; last observation 1999
Site 4 – St. James Parish; last observation 1999; 1998 – 100 to 200 stems in colony about 20 to 30 ft. long; flowering in mid-June.


Global Rank:  
Guide to Global Ranks
Federal Status:  
Guide to Federal Status
Recovery Plan:  

State/Area Protection
  State/Area Rank Status Date  
  Louisiana S1 4/9/1985  
  Mexico SHS1 8/26/1988  
  Texas S2 1/9/1987  

Conservation, Ecology & Research

Ecological Relationships
  • Bumblebees are this specie's primary pollinator.
• Flowers are odorless.
• Flowers are self-compatible.
• Reproduces by underground stems called rhizomes, therefore populations are often composed of clones of one or few individuals (Ulrich 1987).
• Cross-pollinations within clones produce no variation and thus provide limited ability to cope with environmental perturbations.

  • Road widening, weed control and drainage alterations.
• Lack of genetic diversity in clones.
• Scattered and widespread distribution of small numbers of known populations increases this species' vulnerability.

Current Research Summary
  • Soaking the seeds in 500ppm of gibberellic acid for 24 hours and placing them on distilled water-dampened paper improves germination is one method used to promote germination. Germination studies revealed 30% success from seeds air dried at room temperature for 6 months and planted in potting soil mix. Plants were germinated in a greenhouse heated only when outdoor temperatures fell below freezing (Gilmore-McInnis 1990).
• Current seed bank at Mercer Arboretum and Botanic Gardens contains seed from Cameron Parish, LA that date to 1988. Seeds collected from St. James Parish, LA in 1999 were received by Mercer from the LA Natural Heritage Program of LA Dept. of Wildlife and Fisheries in 2002. Plants maintained at Mercer also arose from cuttings from Cameron Parish populations. As this species is a candidate species, maintenance of genetic integrity, documentation of provenance and gene banking is essential.
• At Mercer, plants are very easily propagated from cuttings or divisions. Plants are maintained at Mercer Arboretum and Botanic Gardens for gene banking and also for public display. Plants propagated in our greenhouses are used for display in our Endangered Species Garden and for off-site conservation programs given by Mercer. The Endangered Species Garden, established in 1994 with support from Star Enterprises, displays rare native plants for the public to view year-round. In Spring 2002, the River Oaks Garden Club of Houston, TX provided a generous gift to begin the expansion and renovation of Mercer’s Endangered Species Garden. Plants produced for educational display gardens or for specific restoration and reintroduction projects are produced within Mercer’s nursery and greenhouses and within our Conservation Area. The Conservation Area provides secure, raised beds for mass propagation of plants/seeds. Each bed is provided with independently controlled irrigation and substrates that meet the unique requirements for each species.

Current Management Summary
  • Texas population is monitored by the lead group in Corpus Christi Texas, U.S .Fish and Wildlife Office, the Texas Parks and Wildlife, Austin, Texas.
• Louisiana populations are monitored by The Nature Conservancy and LA Dept. of Wildlife and Fisheries in Baton Rouge, LA.
• Status of Mexican populations presently is unknown.

Research Management Needs
  • Basic biological and ecological studies are needed to facilitate the preservation of this plant.
• Continue surveys to discover and survey sites in TX, LA (and Mexico).
• When possible, rescue from those sites that are in peril. Plants are easily transplanted (Irving 1980).
• Genetic studies to determine distinct populations.
• As this species is a candidate species, maintenance of genetic integrity, documentation of provenance and gene banking is essential.

Monitoring Efforts
  Not Available

Ex Situ Needs
  • Expand gene bank.
• As this species is a candidate species, maintenance of genetic integrity, documentation of provenance and gene banking is essential.
• Continue to improve germination protocols.


Books (Single Authors)

Correll, D.S.; Correll, H.B. 1972. Aquatic and wetland plants of southwestern United States. Stanford, California: Stanford University Press. 1777p.

Correll, D.S.; Correll, H.B. 1975. Aquatic and wetland plants of southwestern United States. 2 vols. Stanford, Calif. Stanford University Press.

Correll, D.S.; Johnston, M.C. 1970. Manual of the vascular plants of Texas. Renner: Texas Research Foundation. 1881p.

Godfrey, R.K.; Wooten, J.W. 1981. Aquatic and wetland plants of southeastern United States: Dicotyledons. Athens: University Georgia Press. 933p.

Lundell, C.L. 1969. Flora of Texas. Renner, Texas: Texas Research Foundation.

Poole, J.M.; Carr, W.R.; Price, D.M.; Singhurst, J.R. 2007. Rare Plants of Texas. College Station, TX. Texas A&M University Press. 640p.

Quintanilla, V. 2001. Listados floristicos de Mexico XXIII. Flora de Coahuila, Mexico, D.F. Instituto de Biologia, Universidad Nacional Autonoma de Mexico.

Thomas, R.D.; Allen, C.M. 1998. Atlas of the vascular flora of Louisiana. Vol. III Dicotyledons (Fabaceae-Zygophyllaceae). Baton Rouge. Louisiana Dept. of Wildlife & Fisheries, Natural Heritage Program.

Books (Sections)

Kartesz, J.T. 1999. A synonymized checklist of the vascular flora of the U.S., Canada, and Greenland. In: Kartesz, J.T.; Meacham, C.A., editors. Synthesis of the North American Flora, Version 1.0. North Carolina Botanical Garden. Chapel Hill, NC.

Electronic Sources

(2002). Digitized herbarium specimen. University of Texas at Austin Herbarium. http://www.lib.utexas.edu/lsl/Mints/physostegia/physostegia.html. Accessed: 2002.

Journal Articles

Cantino, P.D. 1982. A monograph of the genus Physostegia (Labiatae). Contributions from The Gray Herbarium of Harvard University. No. 211: 1-105.

Lundell, C.L. 1959. Studies of Physostegia-I. New species & observations on others. Wrightia. 2(1): 4-12.

Shinners, L.H. 1949. Physostegia correllii (Lundell). comb. nov. Rhodora. 51: 120-22.

Personal Communications

Gilmore-McInnis, N. 1990. Personal communication to Steven Young at Mercer Arboretum and Botanic Gardens.

Poole, J. 2001. Personal communication to Anita Tiller at Mercer Arboretum and Botanic Gardens.

Singhurst, J. 2001. Personal communication to Anita Tiller at Mercer Arboretum and Botanic Gardens.


Faulkner, P. 1999. Rare Plant Species of Louisiana. Louisiana Natural Heritage Program.

Irving, R.S. 1980. Status Report [on Physostegia correllii]. Albuquerque, New Mexico: U.S. Fish & Wildlife Service.

Poole, J.M.; Singhurst, J.R.; Price, D.M.; Carr, W.R. 2002. A List of Rare Plants of Texas. The Nature Conservancy.

Reid, C. 2004. Rare plant species of Louisiana. Baton Rouge. Loisiana Natural Heritage Program.

Ulrich, M. 1997. Unpublished report. Humble, TX: For Mercer Arboretum and Botanic Gardens.


Cantino, P.D. 1980. The Systematics and Evolution of the Genus Physostegia (Labiatae). [Ph.D. Thesis]: Harvard University. 355-359p.

  This profile was updated on 9/28/2010
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