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Home/Species/ Chapman's Skeletongrass

Gymnopogon chapmanianus

A.S. Hitchc.

Chapman's Skeletongrass

G3Vulnerable Found in 1 roadless area NatureServe Explorer →
G3VulnerableGlobal Rank
MediumThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.135729
Element CodePMPOA2Z030
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
Endemicendemic to a single nation
KingdomPlantae
PhylumAnthophyta
ClassMonocotyledoneae
OrderCyperales
FamilyPoaceae
GenusGymnopogon
Other Common Names
Chapman's skeletongrass (EN)
Concept Reference
Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
Taxonomic Comments
Gymnopogon chapmanianus A.S. Hitchc. as treated here includes Gymnopogon floridanus Swallen as a synonym following Hall (1978), Kartesz (1994), Smith in Flora of North America (2003), Weakley and Southeastern Flora Team (2025). However, Gymnopogon floridanus Swallen has been considered a distinct species by Hitchcock and Chase (1950), Smith (1971), and more recently evidence suggests the two may be distinct species, with Gymnopogon floridanus Swallen more closely related to South American taxa, than to Gymnopogon chapmanianus A.S. Hitchc. or other taxa occurring in Florida (Peterson et al. 2014, Peterson et al. 2020).
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2025-04-18
Change Date1999-06-23
Edition Date2025-04-18
Edition AuthorsHardin, E.D. and rev. D. White (1991); rev. M.E. Stover, TNC-HO (1995), L. Morse (1998); rev. L.G. Chafin (1999), rev. C. Nordman (2025).
Threat ImpactMedium
Range Extent20,000-200,000 square km (about 8000-80,000 square miles)
Number of Occurrences81 - 300
Rank Reasons
Chapman's Skeletongrass (Gymnopogon chapmanianus) occurs in the southeastern United States, in southernmost Georgia and in Florida. It is an erect perennial grass, which occurs in longleaf pine sandhills, flatwoods, scrubby flatwoods, scrub, dry prairie and wet prairies. In Georgia it is known from Thomas County, and historically from Charlton County. In Florida it is known from Nassau, Duval, Baker, Dixie, and Wakulla counties south to Collier and Martin counties in southern Florida. It is estimated that there are between 81 and 300 occurrences, and many of the occurrences are on conservation lands, including on Ocala National Forest, Osceola National Forest and Olustee Experimental Forest, Avon Park Air Force Range, on some Florida State Parks, State Forests, and Wildlife Management Areas, and on some other water management district, local or private conservation lands. The loss of habitat with development, and limitations on prescribed fire are ongoing threats to Chapman's Skeletongrass. A schedule of prescribed fire which is appropriate for maintaining the natural ecosystem characteristics where these plants occur will be needed into the future. Invasive exotic plants such as cogongrass are additional threats.
Range Extent Comments
Chapman's Skeletongrass (Gymnopogon chapmanianus) occurs in the southeastern United States, in southernmost Georgia and in Florida. In Georgia it is known from Thomas County, and historically from Charlton County. In Florida it is known from Nassau, Duval, Baker, Dixie, and Wakulla counties south to Collier and Martin counties in southern Florida. The collections from Wakulla County in the Florida Panhandle were identified to Gymnopogon floridanus, included here under the taxonomic concept of Gymnopogon chapmanianus, including Gymnopogon floridanus (Wunderlin 1982, Clewell 1985, Wunderlin 1998, FNA 2003, FNAI 2025, Weakley and Southeastern Flora Team 2025). Range extent was estimated to be about 92000 square kilometers, using herbarium specimens, photo-based observations, and NatureServe Network occurrence data collected between 1994 and 2025 (GBIF 2025, iNaturalist 2025, NatureServe 2025, RARECAT 2025, SEINet 2025).
Occurrences Comments
By applying a 1 km separation distance to herbarium specimens, photo-based observations, and NatureServe Network occurrence data documented between 1994 and 2025, it is estimated that there are between 81 and 300 occurrences of Chapman's Skeletongrass, rangewide (GBIF 2025, iNaturalist 2025, NatureServe 2025, RARECAT 2025, SEINet 2025).
Threat Impact Comments
The loss of habitat with development, and limitations on prescribed fire are ongoing threats to Chapman's Skeletongrass. A schedule of prescribed fire which is appropriate for maintaining the natural ecosystem characteristics where these plants occur will be needed into the future. Invasive exotic plants such as cogongrass are threats (Kral 1983, FNAI 2025).
Ecology & Habitat

Diagnostic Characteristics

Distinguished from G. ambiguus by the awn of the lemma up to 2.5 mm long, usually shorter than the lemma body (vs. 4-10 mm long, longer than the lemma body); and from G. brevifolius by (1) spikelets 2-4-flowered (vs. 1-flowered); (2) panicle branches bearing spikelets nearly to the base (vs. mainly in the upper half of the branch); and (3) first glume 3.8-5.0 mm long (vs. 2.3-3.7 mm long). (Wunderlin 1982, Clewell 1985)

Habitat

Chapman's Skeletongrass occurs in longleaf pine sandhills, sand pine scrub, oak scrub, rosemary scrub, longleaf pine flatwoods, scrubby flatwoods, low sandy pinelands, dry prairie, and wet prairie, at elevations between 5 and 90 meters (Clewell 1985, Wunderlin 1998, FNAI 2025, SEINet 2025, Weakley and Southeastern Flora Team 2025).

Reproduction

Chapman's Skeletongrass flowers from August to December (Weakley and Southeastern Flora Team 2025). Most grasses are wind-pollinated. Dispersal mechanisms in the family include wind (many species' seeds are plumed or winged) and various forms of animal transport.
Terrestrial Habitats
Forest/WoodlandForest - ConiferWoodland - ConiferShrubland/chaparralSavannaGrassland/herbaceous
Palustrine Habitats
HERBACEOUS WETLANDBog/fen
Other Nations (1)
United StatesN3
ProvinceRankNative
FloridaS3Yes
GeorgiaS1Yes
Threat Assessments
ThreatScopeSeverityTiming
1 - Residential & commercial developmentRestricted (11-30%)Serious or 31-70% pop. declineHigh (continuing)
1.1 - Housing & urban areasRestricted (11-30%)Serious or 31-70% pop. declineHigh (continuing)
7 - Natural system modificationsRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
7.1 - Fire & fire suppressionRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
7.1.2 - Suppression in fire frequency/intensityRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
8 - Invasive & other problematic species, genes & diseasesRestricted - smallSerious or 31-70% pop. declineHigh (continuing)
8.1 - Invasive non-native/alien species/diseasesRestricted - smallSerious or 31-70% pop. declineHigh (continuing)

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Plant Characteristics
DurationPERENNIAL, FALL-FLOWERING
Economic Value (Genus)No
Roadless Areas (1)
Florida (1)
AreaForestAcres
Alexander Springs CreekOcala National Forest2,954
References (19)
  1. Clewell, A.F. 1985. Guide to vascular plants of the Florida panhandle. Florida State Univ. Press, Tallahassee, Florida. 605 pp.
  2. Flora of North America Editorial Committee (FNA). 2003a. Flora of North America north of Mexico. Vol. 25. Magnoliophyta: Commelinidae (in part): Poaceae, part 2. Oxford Univ. Press, New York. xxv + 781 pp.
  3. Florida Natural Areas Inventory (FNAI). 2025. Field Guide Account for Chapman's Skeletongrass <i>Gymnopogon chapmanianus</i>. Online. Available: https://www.fnai.org/PDFs/FieldGuides/Gymnopogon_chapmanianus.pdf (Accessed 2025).
  4. Global Biodiversity Information Facility (GBIF). 2025. Global Biodiversity Information Facility (GBIF) data portal. Online. Available: https://www.gbif.org/ (accessed 2025).
  5. Hall, D.W. 1978. The grasses of Florida. Ph.D. Dissertation, University of Florida. Dissertation, U. of Florida. 498 pp.
  6. Hitchcock, A.S. 1951. Manual of the grasses of the United States. 2nd edition revised by Agnes Chase. [Reprinted, 1971, in 2 vols., by Dover Publications, Incorporated, New York.]
  7. Hitchcock, A. S. and A. Chase. 1950. Manual of the grasses of the United States, second edition. USDA miscellaneous Publication No. 200. United States Government Printing Office, Washington. 1051 pp.
  8. iNaturalist. 2025. Online. Available: https://www.inaturalist.org (accessed 2025).
  9. Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
  10. Kral, R. 1983c. A report on some rare, threatened, or endangered forest-related vascular plants of the South. U.S. Dept. of Agriculture Forest Service Technical Publication R8-TP2, Athens, GA. 1305 pp.
  11. NatureServe. 2025. NatureServe Network Biodiversity Location Data. NatureServe, Arlington, Virginia.
  12. Peterson, P.M., K. Romaschenko, and Y. Herrera Arrieta. 2014. A molecular phylogeny and classification of the Cteniinae, Farragininae, Gouiniinae, Gymnopogoninae, Perotidinae, and Trichoneurinae (Poaceae: Chloridoideae: Cynodonteae). Taxon 63(2): 275-286. https://onlinelibrary.wiley.com/doi/pdf/10.12705/632.35
  13. Peterson, P.M., K. Romaschenko, and Y. Herrera Arrieta. 2020. A phylogeny of the Hubbardochloinae including Tetrachaete (Poaceae: Chloridoideae: Cynodonteae). Phytoneuron 2020-81: 1–13. https://www.phytoneuron.net/2020Phytoneuron/81PhytoN-HubbardochloinaePhylogeny.pdf
  14. Small, J.K. 1933. Manual of the southeastern flora. Two volumes. Hafner Publishing Company, New York.
  15. Smith, J.P., Jr. 1971. Taxonomic revision of the genus <i>Gymnopogon</i> (Gramineae). Iowa State Journal of Science 45(3): 319-385.
  16. Southwest Environmental Information Network (SEINet). 2025. Collections Databases. Online. Available: https://swbiodiversity.org/seinet/collections/index.php (accessed 2025).
  17. Weakley, A.S., and Southeastern Flora Team. 2025. Flora of the southeastern United States Web App. Edition of February 18, 2025. University of North Carolina Herbarium (NCU), North Carolina Botanical Garden, University of North Carolina, Chapel Hill. Online. Available: https://fsus.ncbg.unc.edu (accessed 2025).
  18. Wunderlin, R.P. 1982. Guide to the vascular plants of central Florida. Univ. Presses Florida, Gainesville. 472 pp.
  19. Wunderlin, R.P. 1998. Guide to the Vascular Plants of Florida. University Press of Florida: Gainesville, Florida. 806 pp.