Parnassia grandifolia
DC.
Largeleaf Grass-of-Parnassus
G3VulnerableGlobal Rank
HighThreat Impact
tallpaultheforester, CC BY-NC 4.0
tallpaultheforester, CC BY-NC 4.0
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LadysSlipper, CC BY-NC 4.0
Mary Keim, CC BY-NC-SA 4.0
Toby Koosman, CC BY-NC 4.0
Joey Thompson, CC BY-NC 4.0
Identity
Unique IDELEMENT_GLOBAL.2.144987
Element CodePDSAX0P060
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
Endemicendemic to a single nation
KingdomPlantae
PhylumAnthophyta
ClassDicotyledoneae
OrderCelastrales
FamilyCelastraceae
GenusParnassia
Other Common Names
largeleaf grass of Parnassus (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.
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2025-04-30
Change Date2025-04-30
Edition Date2025-04-24
Edition AuthorsWeakley (1994), rev. L. Morse (1998, 2000), rev. C. Nordman (2025).
Threat ImpactHigh
Range Extent200,000-2,500,000 square km (about 80,000-1,000,000 square miles)
Number of Occurrences81 to >300
Rank Reasons
Largeleaf Grass-of-Parnassus (Parnassia grandifolia) occurs in the eastern United States, in the Appalachians, Interior Low Plateau, Interior Highlands and widely disjunct areas of the Coastal Plain. It occurs in scattered locations from Virginia and West Virginia, west to Missouri and eastern Texas, and occurs disjunct in the Florida Panhandle, Florida Peninsula, and southeastern North Carolina. It is a perennial plant with round leaves and white flowers which occurs in wetlands, especially with calcareous seepage. It is rare across its range except it is considered just uncommon in Arkansas and Missouri, it is estimated there are more than 150 occurrences. It is known from the Apalachicola, De Soto (on Camp Shelby), Kisatchie, Mark Twain, Pisgah, Ocala, and Ozark National Forests, and from some state parks, natural areas, nature preserves, and wildlife management areas. It is threatened by filling and other impacts to wetlands, land-use conversion and habitat fragmentation, such as from road construction and residential or commercial development. Intensive forest management practices (such as skidder or logging road crossings, herbicide or mechanical site preparation), canopy closure from competing shrubs, invasive exotic grasses such as Arthraxon hispidus, Microstegium vimineum, Schedonorus arundincaeus and rooting by feral hogs are also threats.
Range Extent Comments
Largeleaf Grass-of-Parnassus (Parnassia grandifolia) occurs in the eastern United States, in the Appalachians, Interior Low Plateau, Interior Highlands and widely disjunct areas in the Coastal Plain. It occurs in scattered locations from Virginia and West Virginia, west to Missouri, Arkansas, southeastern Oklahoma, eastern Texas, Louisiana, southern Mississippi, and is disjunct in the Florida Panhandle, Florida Peninsula, and southeastern North Carolina. It is rare across its range except it is considered just uncommon (not rare) in the Interior Highlands of Missouri and Arkansas (Gentry et al. 2013, FNA 2016, FNAI 2025, GBIF 2025, John Logan, pers. comm., 1993, MacRoberts et al. 1997, Weakley and Southeastern Flora Team 2025). Range extent was estimated to be about 1,140,000 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 150 or more occurrences of Parnassia grandifolia, rangewide (GBIF 2025, iNaturalist 2025, NatureServe 2025, RARECAT 2025, SEINet 2025). It is considered rare throughout its range and just uncommon (not rare) in the Interior Highlands of Missouri and Arkansas (Weakley and Southeastern Flora Team 2025). There have been over 100 locations reported for this species in Arkansas (John Logan, pers. comm., 1993).
Threat Impact Comments
Parnassia grandifolia is rare wherever it occurs east of the Mississippi River, making it especially threatened by filling and other impacts to wetlands, land-use conversion and habitat fragmentation (Southern Appalachian Species Viability Project 2002), this may be from impacts of road construction and residential or commercial development. Intensive forest management practices (such as skidder or logging road crossings, herbicide or mechanical site preparation) could irreparably damage the fragile wetland habitat of this species. Canopy closure from competing shrubs, invasive exotic grasses which may invade wetlands such as Arthraxon hispidus, Microstegium vimineum, Schedonorus arundincaeus and rooting by feral hogs are threats (NatureServe 2025).
Ecology & Habitat
Diagnostic Characteristics
Three species of Parnassia can be found in the southeastern United States; P. asarifolia, P. caroliniana, and P. grandifolia. P. asarifolia occurs in the mountains, has clawed petals, reniform basal leaves, and fertile stamens exceeding the staminoida. P. caroliniana and P. grandifolia do not have clawed petals and have round leaves and stamens shorter than the staminodia. P. grandifolia has a short, erect rhizome or rootstock and elliptic petals with 5-9 veins (counted at a point halfway between the base and the apex and ignoring short laterals), and green ovary, whereas P. caroliniana has a long, creeping, horizontal rhizome and oval petals with 11 -17 veins (counted at a point halfway between the base and the apex and ignoring short laterals), and white ovary, it tends to form clonal patches to several meters in diameter (Godfrey and Wooten 1981, Radford et al. 1968, Weakley and Southeastern Flora Team 2025).
Habitat
Largeleaf Grass-of-Parnassus (Parnassia grandifolia) occurs in savannas, bogs, ecotonal seepage slopes between pine-hardwood or mesic pine flatwoods and swamps, calcareous seeps, fens, meadows, and springs, at elevations between about 6 and 1400 meters (Goodfrey and Wooten 1981, MacRoberts et al. 1997, Gentry et al. 2013, FNA 2016). In "fens, gravelly seepages, inland primarily or solely over calcareous, mafic, or ultramafic rocks; in the Coastal Plain in seepage over marl [such as] on nearly vertical river bluffs on the Cape Fear River (NC), and in acidic seepage bogs in pinelands" (Weakley and Southeastern Flora Team 2025). In the Interior Highlands of Missouri, it "occurs in swampy open meadows in small valleys fed by calcareous spring water, moist limestone ledges along streams, and moist crevices at the base of north-facing limestone bluffs" (Steyermark 1963). In North Carolina "it occurs mainly over mafic rocks in the Mountains, such as over amphibolite. Sites are damp to wet, such as fens, gravelly seepages, and rarely in bogs. Near the coast, the populations are in seepages on steep bluffs, over marl rock" (LeGrand et al. 2025). In Florida, it occurs in "wet habitats including open grassy wet prairies and seepage slopes as well as hydric hammocks and edges of swamps along rivers and streams" (FNAI 2025).
Reproduction
Parnassia grandifolia flowers from August to November (Weakley and Southeastern Flora Team 2025), it is pollinated by insects, including Diptera and Hymenoptera.
Terrestrial Habitats
Woodland - HardwoodWoodland - ConiferWoodland - MixedSavannaGrassland/herbaceous
Palustrine Habitats
HERBACEOUS WETLANDBog/fen
Other Nations (1)
United StatesN3
| Province | Rank | Native |
|---|---|---|
| Kentucky | S1 | Yes |
| Texas | S1 | Yes |
| Arkansas | S3 | Yes |
| Oklahoma | S1 | Yes |
| Alabama | S1 | Yes |
| Louisiana | S1 | Yes |
| West Virginia | S1 | Yes |
| North Carolina | S2 | Yes |
| Mississippi | S2 | Yes |
| South Carolina | S2 | Yes |
| Missouri | S3 | Yes |
| Virginia | S2 | Yes |
| Georgia | S1 | Yes |
| Florida | S2 | Yes |
| Tennessee | S3 | Yes |
Threat Assessments
| Threat | Scope | Severity | Timing |
|---|---|---|---|
| 1 - Residential & commercial development | Restricted (11-30%) | Serious or 31-70% pop. decline | High (continuing) |
| 1.1 - Housing & urban areas | Restricted (11-30%) | Serious or 31-70% pop. decline | High (continuing) |
| 4 - Transportation & service corridors | Small (1-10%) | Serious or 31-70% pop. decline | High (continuing) |
| 4.1 - Roads & railroads | Small (1-10%) | Serious or 31-70% pop. decline | High (continuing) |
| 5 - Biological resource use | Restricted (11-30%) | Serious or 31-70% pop. decline | High (continuing) |
| 5.3 - Logging & wood harvesting | Restricted (11-30%) | Serious or 31-70% pop. decline | High (continuing) |
| 8 - Invasive & other problematic species, genes & diseases | Small (1-10%) | Serious or 31-70% pop. decline | High (continuing) |
| 8.1 - Invasive non-native/alien species/diseases | Small (1-10%) | Serious or 31-70% pop. decline | High (continuing) |
Plant Characteristics
DurationPERENNIAL
Economic Value (Genus)No
Roadless Areas (8)
Arkansas (2)
| Area | Forest | Acres |
|---|---|---|
| Clifty Canyon | Ozark-St. Francis National Forest | 1,963 |
| Little Blakely | Ouachita National Forest | 3,342 |
Missouri (2)
| Area | Forest | Acres |
|---|---|---|
| Irish Rare II Study Area | Mark Twain National Forest | 1,226 |
| Spring Creek Rare II Study Area | Mark Twain National Forest | 4,899 |
North Carolina (4)
| Area | Forest | Acres |
|---|---|---|
| Boteler Peak | Nantahala National Forest | 4,205 |
| Cherry Cove (addition) | Nantahala National Forest | 836 |
| Chunky Gal (addition) | Nantahala National Forest | 3,336 |
| Tusquitee Bald | Nantahala National Forest | 13,670 |
References (17)
- Flora of North America Editorial Committee (FNA). 2016. Flora of North America north of Mexico. Vol. 12. Magnoliophyta: Vitaceae to Garryaceae. Oxford Univ. Press, New York. xxiv + 603 pp.
- Florida Natural Areas Inventory (FNAI). 2025. Field Guide Account for Large-leaved Grass-of-Parnassis <i>Parnassia grandifolia</i> DC. Online. Available: https://www.fnai.org/PDFs/FieldGuides/Parnassia_grandifolia.pdf (Accessed 2025).
- Gentry, J.L., G.P. Johnson, B.T. Baker, C.T. Witsell, and J.D. Ogle, eds. 2013. Atlas of the Vascular Plants of Arkansas. University of Arkansas Herbarium, Fayetteville, Arkansas. Online. Available: https://www.arkansasheritage.com/docs/default-source/arkansas-natural-heritage-commission-documents/atlas-of-the-vascular-plants-of-arkansas_2020-download.pdf (Accessed 2025).
- Global Biodiversity Information Facility (GBIF). 2025. Global Biodiversity Information Facility (GBIF) data portal. Online. Available: https://www.gbif.org/ (accessed 2025).
- Godfrey, R.K., and J.W. Wooten. 1981. Aquatic and wetland plants of southeastern United States: Dicotyledons. Univ. Georgia Press, Athens. 933 pp.
- iNaturalist. 2025. Online. Available: https://www.inaturalist.org (accessed 2025).
- 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.
- LeGrand, H., B. Sorrie, and T. Howard. 2025. Vascular Plants of North Carolina [Internet]. Raleigh (NC): North Carolina Biodiversity Project and North Carolina State Parks. Online. Available: https://auth1.dpr.ncparks.gov/flora/index.php (accessed 2025).
- Logan, John. Botanist, Arkansas Natural Heritage Program.
- MacRoberts, B. R., M. H. MacRoberts, L. M. Stacey and D. C. Moore. 1997b. The status of <i>Parnassia</i> (Saxifragaceae) in the West Gulf Coastal Plain. Phytologia 83:53-57.
- NatureServe. 2025. NatureServe Network Biodiversity Location Data. NatureServe, Arlington, Virginia.
- Radford, A.E., H.E. Ahles, and C.R. Bell. 1968. Manual of the vascular flora of the Carolinas. Univ. North Carolina Press, Chapel Hill, NC. 1183 pp.
- Sorrie, B.A. and S.W. Leonard. 1999. Noteworthy records of Mississippi vascular plants. Sida 18(3):889-908.
- Southern Appalachian Species Viability Project. 2002. A partnership between the U.S. Forest Service-Region 8, Natural Heritage Programs in the Southeast, NatureServe, and independent scientists to develop and review data on 1300+ regionally and locally rare species in the Southern Appalachian and Alabama region. Database (Access 97) provided to the U.S. Forest Service by NatureServe, Durham, North Carolina.
- Southwest Environmental Information Network (SEINet). 2025. Collections Databases. Online. Available: https://swbiodiversity.org/seinet/collections/index.php (accessed 2025).
- Steyermark, J.A. 1963. Flora of Missouri. Iowa State Univ. Press, Ames. 1728 pp.
- 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).