Fen Grass of Parnassus is a perennial herb growing to two feet high with an erect unbranched flowering stem.
Leaves: Leaves are mostly all basal, forming a rosette at ground level. They are leathery, oblong to ovate (longer than wide), the larger leaves almost 3 inches long and 2 inches wide. The tips are obtuse, the bases vary from wedge shape to slightly heart-shaped. All are stalked. Some plants may have a leaf on the lower part of the stem that appears to be stalkless, but actually has the stalk embedded in the stem.
The Inflorescence is a terminal single flower atop the flowering stem.
Flowers are bisexual with the hypanthium absent or fused to the ovary. There are 5 very short sepals, oblong to ovate, tips rounded, margins whitish to translucent (hyaline). These reflex when fruit is formed. The 5 petals are white, showy, shaped like the sepals but 2 to 4 times as long. They have 5 to 12 conspicuous greenish veins. Petal margins do not have fringes as some members of this genus do, but the margin may be wavy. Stamens number 5 with white filaments and anthers brownish at maturity. These are placed opposite the sepals. Five staminodes (false stamens) are placed between them. These are shorter than the stamens, They have a nectar pad at their base and each has 3 erect rays, with a yellow rounded gland at the tip. These surround the green ovary, which lacks a style.
Pollination in this plant family takes place when one stamen bends inward and the anther empties its pollen to a receptive stigma slit on the ovary, and then bends back upright. Then another stamen does the same, and so on until the process is complete. The ovary is divided into (usually) 4 carpels but the division walls are incomplete, such that the upper part is, in effect, one cell.
Seed: Fertile flowers produce a dry ovoid seed capsule of one chamber, 12-14 mm long, which contains many very small seeds.
Habitat: Fen Grass of Parnassus prefers moist to wet sites with base soils neutral to base - that is, calcereous soils. The root system has a caudex and fibrous roots.
Names: The genus name Parnassia thought to refer to Mount Parnassus in Greece. There are 70 species of this genus in the world, many in Europe and Asia. The species name glauca , refers to the fine whitish bloom that occurs on plants stems and leaves.
The author name for the plant classification, from 1840 - ‘Raf.’ is for Constantine Samuel Rafinesque, (1783-1840), European polymath who traveled in the United States, lived here many years, collected specimens, and published over 6,700 binomial names for plants. He applied to be botanist on the Lewis & Clark expedition but Jefferson turned him down in favor of training Lewis to act as botanist and saving the expense of another person.
Plant family changes: For many years the Parassiaceae was a separate family. Then it was treated as a part of the Saxifrage (Saxifragaceae) family. Now, based on molecular work, the Angiosperm Phylogeny Group in 2009 decided to place the Parnassiaceae into the Celastraceae (Bittersweet) family. The authorities at the University of Minnesota Herbarium have made this change on their checklist (Ref. #W4); and FNA has done likewise in Volume 12. (Ref. #W7)
Comparisons: The only other species of Parnassia found in Minnesota is P. palustris. That species does not have hyaline sepal margins, the petals are 1.5 to 2x the length of the sepals, usually have fewer veins and those veins do not reach the margin of the petal. Also, the staminodes are divided into 9 or more segments at their tips. There is some overlap in the counties where both species are found, but generally P. Palustris is found in the northern 2/3rds of the State and P. glauca in the southern third.
Above: The flowering stems rise above basal rosettes of leaves. Drawing ©USDA-NRCS Wetland Handbook.
Below: The five petals have a vein pattern that appears embossed. Surrounding the central greenish ovary are 5 staminodes, each with 3 rays ending in a yellow globular gland. The five fertile stamens rise much higher between the petals. The sepals are smaller and not visible from the flower face.
Below: The rosette of basal leaves around the flowering stem.
Notes: Fen Grass of Parnassus is indigenous to the Garden. Eloise Butler noted it in bloom on Sept. 20, 1908. She listed it as Parnassia caroliniana which is a bit of a stumper as that species grows in the SE United States and nowhere near Minnesota. The resolution of this is a notation in Flora of North America Volume 12, that P. caroliniana had been misapplied to P. glauca in early references such as 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.
In 1916 she again noted the plant in bloom; on Aug. 28, 1917 she transplanted a clump from a meadow near the Luce Line RR and in 1925 from Superior Blvd (both places in Hennepin County). She did not give a botanical name, but no other species of Parnassia in Minnesota has never been found in the county. It was not until 1924 and 1927 that she brought in P. palustris and those plants came from Northern Minnesota.
This brings us to Martha Crone's records where she notes planting P. caroliniana in 1934 and seeds in 1936. Then we jump to 1947 where she brings in 60 plants from Carver County and in 1948, 100 plants from LeSeur County. In neither instance does she list the scientific name, but only P. glauca has been collected in those counties, so we presume that was what she planted. In 1949 30 plants come in without a source and in her 1951 census she only lists P. palustris. So did all the earlier P. glauca die out? did she miss them? or did they die out and the 1949 plantings were P. Palustris? We do not know.
North America: As noted above the photo section, there are only two species of Parnassia found in Minnesota. There are nine species in North America and about 70 world wide. Fen Grass of Parnassus is found in North America from the east coast westward in the northern tier of U.S. states as far west as the Dakotas and in Canada as far west as Saskatchewan along the tier of Lower Provinces.
Uses: The various species of Parnassia are grown for their appearance. There is little literature on medicinal uses.
References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applied. Distribution principally from W1, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.
Identification booklet for most of the flowering forbs and small flowering shrubs of the Eloise Butler Wildflower Garden. Details Here.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"