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Parnassia grandifolia DC.
Largeleaf Grass-of-Parnassus
Federal Protection: No US federal protection
State Protection: No Georgia state protection
Global Rank: G3
State Rank: S1
Element Locations Tracked in Biotics: Yes
SWAP 2015 Species of Greatest Conservation Need (SGCN): No
SWAP 2025 Species of Greatest Conservation Need (SGCN): Yes
2025 SGCN Priority Tier: High Conservation Concern
Element Occurrences (EOs) in Georgia: 3
Habitat Summary for element in Georgia: Seeps over ultramafic gravelly substrate
Perennial herb, forming clusters of slightly succulent, glossy leaves. Leaf blades are 1 - 4 inches (3 - 10 cm) long, oval, usually longer than broad, with long leaf stalks; leaf bases are rounded but not deeply heart-shaped (in spite of the common name, the leaves does not resemble grass leaves in any way). The flower is about 1.4 inches (3 - 4 cm) across, solitary at the top of a long stalk that bears one leaf about halfway. Petals are five in number, white, oval, with 5 - 9 green, brown, or yellow main veins; the lower veins have short side veins with dilated tips. The ovary is green, sometimes white near the base.
Kidney-leaf Grass-of-Parnassus (Parnassia asarifolia) occurs in acidic mountain wetlands and along small streams. Its leaves are kidney-shaped, as wide as or wider than they are long. Its petals are blunt-tipped and nearly as wide as they are long with clawed bases (see drawing).
None in Georgia.
Seepage wetlands (fens) with neutral or alkaline water developed over bedrock high in magnesium or calcium.
Large-leaved Grass-of-Parnassus is a perennial herb that reproduces sexually by seed. Its flowers must be cross-pollinated in order to set seed; the stamens shed pollen before the stigmas are receptive, thus preventing self-pollination. Stamens also ripen and shed pollen in succession, one after another, extending the period for pollen collection. The flowers have 5 fertile stamens and 5 clusters of non-fertile stamens (staminodia). The staminodia have glistening tips which, along with the bright veins on the petals, attract bees and flies to the center of the flower. These insects transfer pollen from other flowers in the process of collecting the nectar that is secreted at the base of each staminode.
Although Large-leaved Grass-of-Parnassus leaves are distinctive throughout the growing season, surveys are best conducted during flowering (September–October) when plants are most conspicuous.
Georgia, Florida, Alabama, Mississippi, Louisiana, Texas, South Carolina, North Carolina, Tennessee, Virginia, West Virginia, Kentucky, Missouri, Arkansas, and Oklahoma.
Destruction of habitat by clearing or development. Changes in hydrology which divert or stop seepage flow. Trampling and grazing by cattle. Browsing by deer. Invasion by exotic pest plants. Digging by feral hogs.
| Threat 1 | Threat 2 | Threat 3 | |
|---|---|---|---|
| General Threat | Human intrusions & disturbance | Natural system modifications | Invasive & other problematic species, genes & diseases |
| Specific Threat | None | None | None |
Two populations of Large-leaved Grass-of-Parnassus were discovered in the 1800s in Catoosa and Rabun (or possibly Habersham) counties; neither of these sites has been re-located. One population was recently discovered in Towns County in a seepy wetland on state-owned land. Large-leaved Grass-of-Parnassus is ranked S1 by the Georgia Department of Natural Resources, indicating that it is critically imperiled in Georgia.
Protect all mountain wetlands, especially seeps, springs, fens, and bogs, from disturbance to hydrology and soils. Exclude cattle from around springs and seeps. Control exotic pest plants and feral hog populations. Remove encroaching woody plants by hand.
Albrecht, M., and Q. Long. 2014. Germination niche of the permanent wetland specialist, Parnassia grandifolia DC. Seed Science Research 24(3): 239-245. doi:10.1017/S0960258514000166
Chafin, L.G. 2000. Field guide to the rare plants of Florida. Florida Natural Areas Inventory, Tallahassee.
GADNR. 2020. Element occurrence records for Parnassia grandifolia. Georgia Department of Natural Resources, Wildlife Resources Division, Social Circle, Georgia.
Godfrey, R.K. and J.W. Wooten. 1981. Aquatic and wetland plants of southeastern United States, Vol. 2, dicotyledons. University of Georgia Press, Athens.
NatureServe. 2019. Parnassia grandifolia comprehensive report. NatureServe Explorer. Arlington, Virginia. http://explorer.natureserve.org/servlet/NatureServe?searchName=Parnassia+grandifolia
Radford, A.E., H.E. Ahles, and C.R. Bell. 1968. Manual of the vascular flora of the Carolinas. University of North Carolina Press, Chapel Hill.
Sandvik, S.M. and Ø. Totland. 2003. Quantitative importance of staminodes for female reproductive success in Parnassia palustris under contrasting environmental conditions. Canadian Journal of Botany 81(1): 49-56.
Swales, D.E. 1979. Nectaries of certain Arctic and sub-Arctic plants with notes on pollination. Rhodora 81: 363-407. https://www.jstor.org/stable/23311088
Weakley, A.S. 2015. Flora of the southern and mid-Atlantic States. University of North Carolina Herbarium, University of North Carolina, Chapel Hill. http://www.herbarium.unc.edu/flora.htm
Linda G. Chafin
L. Chafin, Jul. 2008: original account
K. Owers, Feb. 2010: added pictures
L. Chafin, Mar. 2020: updated original account.
