NORTH CAROLINA’S GRASS–OF-PARNASSUS SPECIES

NORTH CAROLINA’S 

GRASS–OF-PARNASSUS SPECIES

Figure 1: Parnassia asarifolia the Kidney-leaved Grass-of-Parnassus

 

Grass-of-Parnassus or Bog Stars species are favorites of many people due to the intricate and contrasting green veining on the white petals. There are approximately seventy species worldwide and nine species in North America¹. Parnassia are found through-out the Northern Hemisphere in moist habitats ranging from alpine meadows, fens, bogs, seeps, and swamps.  North Carolina is lucky to have three species of Parnassia; P. asarifolia the Kidney-leaved Grass-of-Parnassus, P. grandifolia the Bigleaf Grass-of-Parnassus, and P. caroliniana the Carolina or Savanna Grass-of-Parnassus.

Table 1: Summary of characteristics of North Carolina Parnassia species.

Parnassia asarifolia Kidney-leaved Grass-of-Parnassus	Parnassia grandifolia Bigleaf Grass-of-Parnassus	Parnassia caroliniana Carolina Grass-of-Parnassus
Basal leaves basically reniform to orbiculate with cordate bases, often wider than long	Basal leaves ovate, leaf bases rounded to subcordate, longer than wide	Basal leaves broadly ovate, leaf bases rounded to subcordate
Ovary white - greenish	Ovary green sometimes whitish at base	Ovary white
Petals are clawed	Petals not clawed	Petals not clawed
Each petal has 11-15 major parallel veins2	Each petal has 5-9 major parallel veins3	Each petal has 11-17 major parallel veins3
5 – three-lobed staminodes	5 – three-lobed staminodes	5 – three-lobed staminodes
Staminodia shorter than stamens ( be careful of this trait – check mature flowers)	Staminodia longer than stamens	Staminodia shorter than stamens
Prefers moist acidic environments	Prefers moist more basic, calcareous environments	Prefers moist more basic, calcareous environments

Parnassia asarifolia or the Kidney-leaved Grass-of-Parnassus is uncommon in North Carolina but, is probably the most commonly seen species in our state. It is restricted to the mountains and is sometimes referred to as the Appalachian Grass-of-Parnassus. As the name implies it has a basal rosette of reniform-orbiculate leaves with cordate bases (Figures 2, 3). The flowers have five sepals and five clawed white petals with the typical intricate green veining (Figures 4, 5, 6, 7, 8). To me this is our most beautiful species because the petals have undulating margins. The gynoecium (female reproductive structures) has a superior, four connate carpellated ovary with a short style and four stigmas.  The androecium (male reproductive structures) is composed of five stamens and five sterile nectariferous staminodes. The staminodia are deeply three lobed and give the impression there are fifteen (Figures 4, 5, 6).  This species blooms in late fall and can be seen at high elevation roadside seeps along the Blue Ridge Parkway. 

Figure 2: Basal rosette of Parnassia asarifolia or Kidney-leaved Grass-of-Parnassus leaves showing the reniform-orbiculate leaves with cordate bases. Notice most leaves are wider than long.

Figure 3: Kidney-leaved Grass-of-Parnassus leaf showing the strong cordate base.

Figure 4: Flower morphology of Parnassia asarifolia. Notice the clawed petals, this feature is not found in P. grandifolia and P. caroliniana. Also, notice the stamen longer than the staminodia, another feature unique (among the N.C. species) to P. asarifolia.

Figure 5: A close-up of a Parnassia asarifolia petal showing the intricate green veining. P. asarifolia has 11-15 major parallel veins per petal. Also note the deeply three-lobed staminode (center) and how it is shorter than the stamen.

Figure 6: Kidney-leaved Grass-of-Parnassus, Parnassia asarifolia, flower. Notice the five stamen and the sterile staminodia.

Figure 7: Kidney-leaved Grass-of-Parnassus, Parnassia asarifolia, flower and bud.

Figure 8: Drawing of Parnassia asarifolia, Kidney-leaved Grass-of-Parnassus.

USDA-NRCS PLANTS Database / Britton, N.L., and A. Brown. 1913. An illustrated flora of the northern United States, Canada and the British Possessions. 3 vols. Charles Scribner's Sons, New York. Vol. 2: 212.

Figure 9: Flowers of Kidney-leaved Grass-of-Parnassus, Parnassia asarifolia. Notice that these are freshly opened flowers and the stamen have not elongated yet and appear shorter than the staminodia.

The Bigleaf Grass-of-Parnassus, Parnassia grandifolia, is rare and rated as threatened in North Carolina and federally is listed as a species of special concern. It can be found in both the mountains and in several coastal counties. Along the coast it often grows in concurrence with P. caroliniana. Although P. grandifolia and P. caroliniana have many characteristics in common the former can be distinguished by having a green ovary rather than white, and by having fewer major veins on the petals, (5-9 veins in P. grandifolia verses 11-17 in P caroliniana) (Table 1)(Figures 10, 11, 12, 14). In the mountains it is found primarily in fens and seepages over mafic or calcareous rock. Bigleaf Grass-of-Parnassus can be separated from P. asarifolia by its dark green ovary, lack of clawed petals, leaves that are longer than wide (Figure 13), staminodia longer than the stamens, and more narrow petals with fewer green veins (5-9 veins in P. grandifolia versus 11-15 in P, asarifolia) (Table 1).

Figure 10: A drawing of  Bigleaf Grass-of-Parnassus, Parnassia grandifolia. USDA-NRCS PLANTS Database / Britton, N.L., and A. Brown. 1913. An illustrated flora of the northern United States, Canada and the British Possessions. 3 vols. Charles Scribner's Sons, New York. Vol. 2: 212.

Figure 11: A close-up of a Bigleaf Grass-of-Parnassus, Parnassia grandifolia, flower showing the green ovary, staminodia longer than the stamen, and 5-9 major parallel green veins on each petal.

Figure 12. A close-up of a Bigleaf Grass-of-Parnassus, Parnassia grandifolia, petal showing the beautiful and intricate green veining.

Figure 13: Ovate leaves of Bigleaf Grass-of-Parnassus, Parnassia grandifolia.  Notice they are longer than wide.

Figure 14: Bigleaf Grass-of-Parnassus, Parnassia grandifolia, flower.

Parnassia caroliniana, Carolina Grass-of-Parnassus, is endangered in North Carolina. The specific epithet, “caroliniana’, is very apt since this species is primarily found in North and South Carolina with a disjunct population in the Florida Panhandle. It grows in a few of our more southern coastal counties in seepage areas, bogs, and wet pine or cypress savannas often underlain with coquina limestone³. The latter plant communities have been greatly reduced due to draining, the lumber industry, and development. They are also fire dependent and without regular prescribed fire burns many of our rare coastal plants such as Venus flytrap (Dionaea muscipula), Rough-leaved Loosestrife (Lysimachia asperulifolia), Carolina Grass-of-Parnassus (Parnassia caroliniana), Sandhills Lily (Lilium pyrophilum), Pixie-moss (Pyxidanthera brevifolia) and the Pine Barren Gentian (Gentiana autumnalis) would cease to exist in North Carolina. The Carolina Grass-of-Parnassus blooms in late summer and fall. My photographs of the plant blooming were taken in mid-November (Figures 15, 16,  17, 18, 19). Even though this is the rarest of our three species I find it to be the least eye-catching. 

Figure 15: Carolina Grass-of-Parnassus, Parnassia caroliniana, flower showing a nice view of the five deeply three-lobed staminodia.

Figure 16: A close-up of a Carolina Grass-of-Parnassus, Parnassia caroliniana, flower petal showing the 11-17 major parallel green veins.

Figure 17: Carolina Grass-of-Parnassus, Parnassia caroliniana, flower, note the white ovary.

Figure 18: Carolina Grass-of-Parnassus, Parnassia caroliniana, leaves.

Figure 19. Carolina Grass-of-Parnassus, Parnassia caroliniana, flower in bud.

I hope you have enjoyed learning about our state Parnassia species. The future of these beautiful species and other rare species in North Carolina depends on various conservation efforts. If you enjoy and value North Carolina’s unique flora and fauna please consider joining and supporting some of the organizations listed below. 

Audubon Society in North Carolina  http://nc.audubon.org/
Friends of Plant Conservation   https://www.ncplantfriends.org/
North Carolina Native Plant Society  http://www.ncwildflower.org/
North Carolina Natural Heritage Program  https://www.ncnhp.org/
North Carolina Sandhills Conservation Partnership  http://www.ncscp.org/
Southern Appalachian Highlands Conservancy  https://appalachian.org/
The Nature Conservancy in North Carolina  https://www.nature.org/ourinitiatives/regions/northamerica/unitedstates/northcarolina/index.htm

“Unless someone like you cares a whole awful lot,
Nothing is going to get better. It's not.”

 Dr. Seuss, The Lorax

Resources:

1. Ball, Peter W. “Parnassia.” Parnassia in Flora of North America @ Efloras.org, www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=124074. 

2. Radford, Albert Ernest, Harry E. Ahles, and Clyde Ritchie Bell. Manual of the Vascular Flora of the Carolinas. Chapel Hill, NC: U of North Carolina Press, 1983. Print.

3. Weakley, Alan S. Flora of the Southern and Mid-Atlantic States. Chapel Hill, NC: U of North Carolina Herbarium, North Carolina Botanical Garden, U of North Carolina, Chapel Hill, 2015. Print.

4. Phillips, R. B. 1980. Systematics of Parnassia L. (Parnassiaceae): Generic Overview and Revision of North American Taxa. Ph.D. dissertation. University of California, Berkeley.

5. “Parnassia caroliniana.” Results Detailed Report, explorer.natureserve.org/servlet/NatureServe?searchName=Parnassia%2Bcaroliniana. 

6. All photos, unless otherwise noted, were taken and are property of Tracie Jeffries.