A new plant family for Oregon
by Henrietta L. Chambers
As I began working on the genus Parnassia for the checklist, I was mystified that I could not find it in the Intermountain Flora. Naturally I looked in the Saxifragaceae, and when it was not there, I assumed the genus was absent in the intermountain region. However, in the herbarium I found that we had specimens from Steens Mountain, which is part of that area. In the Intermountain Flora index, I found the family Parnassiaceae and lo, the mystery was solved! Noel and Patricia Holmgren did the treatment, and it is from this source that I have taken most of my information.
It is exciting when a new plant species is discovered in our state, as that may mean a new genus or family to add to our totals. That is not the case here. One species of Parnassia was collected on the northwest coast of America more than 200 years ago (1792) by Archibald Menzies and was named Parnassia fimbriata by K. D. Koenig in 1804. The genus was placed in the family Parnassiaceae by Leroy Abrams in his Illustrated Flora of the Pacific States. Abrams was probably influenced by Britton and Brown’s Illustrated Flora of the United States and Canada (1913). Recent studies by D. R. Morgan and D. E. Soltis (1993), based on rbcL sequence data, show that Parnassia is very distant from other genera in the Saxifragaceae. Thus I am following the lead of Abrams and the Holmgrens by placing it in its own family.
We have three species of grass-of-Parnassus in Oregon. The common name is derived from Mount Parnassus in central Greece and was used for a plant reported by Dioscorides, the famous first century Greek physician. That plant was probably P. palustris, the species with the widest distribution in the genus. The most common and widespread taxon in western North America is Parnassia fimbriata (fringed grass-of-Parnassus), which occurs throughout western North America from Alaska as far south as New Mexico. In Oregon, it is found from the central Cascades to the Wallowa Mountains. It grows in meadows, wooded seeps, along stream banks and lakeshores. The species name comes from the numerous petaloid protuberances (fimbriae), which are 1-5 mm long and arise on the petal margin from the base of the petals to the middle. The oldest collection of this species in the OSU Herbarium was made in 1906 at Updyke Falls, Deschutes County, near Tumalo. There are many collections from the Wallowa Mountains at 5200 to7200 foot elevations.
Of the three Oregon parnassias, P. fimbriata has the broadest leaves. These are widest below the middle and cordate-based. The basal leaves have prominent veins and show a similarity to our native lily of the valley (Maianthemum dilatatum). A single small, sessile leaf appears near midlength on the flowering stem (see illustration). The 5 staminodes, which alternate with the stamens, are fleshy, club-shaped, and have short marginal protuberances, mainly near the top.
California grass-of-Parnassus, Parnassia californica, occurs in northern California and in the Siskiyou Mountains of Josephine and possibly Curry Counties. It grows in swamps, moist woods, and darlingtonia bogs. The oldest collection is one by Thomas Howell in 1889; the label reads “Oregon Coast Mountains, 42nd parallel.” Parnassia californica has ovate to lance-ovate leaves with tapering bases and a single flowering stalk with a small, sessile bract above mid-length. The staminodes have numerous long, slender filaments with yellow, glandular tips. The most obvious difference that separates P. californica from P. fimbriata and P. cirrata, is that its petals lack fimbriae.
Cascade grass-of-Parnassus, Parnassia cirrata var. intermedia grows in the Cascades of southern Washington and Oregon, Steens Mountain, southern Idaho, and north and central Nevada. It too likes wet habitats such as bogs, mires, grassy lake borders, shaded stream banks, and wet meadows. It combines some of the features of the above-mentioned species: it has the fimbriate petals of P. fimbriata, and the staminodes with long slender filaments topped with glands which are characteristic of P. californica. The oldest collection in the OSU Herbarium was by L. F. Henderson in 1884, in wet sphagnum at Lost Lake in Hood River County. The typical variety has a more southerly distribution in the San Bernardino and San Gabriel Mountains of California.
Another western species, P. kotzebuei, does not occur in Oregon, but is found in nearby states. The species is circumboreal in its distribution and occurs as far south as the mountain regions of Washington, Idaho and Montana. The OSU Herbarium has several collections from Alaska, and they show a plant with much smaller flowers and leaves than our Oregon taxa.
Key to Oregon Parnassia
1. Petals with entire margins; leaves tapering at base; staminodes with 15 or more globose-tipped filaments . . . . . . . . . . . P. californica
1. Petals with marginal fimbriae; leaves with cordate bases; staminodes various
2. Staminodes with 7-10 slender globose-tipped filaments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .P. cirrata var. intermedia
2. Staminodes fleshy, club-shaped with short marginal protuberances, not globose-tipped . . . . . . . . . . . . . . . . . . . . . . . . . .P. fimbriata
Reference: Phylogenic relationships among members of Saxifragaceae sensu latu based on rbcL sequence data. Ann. Missouri Bot. Gard. 80: 631-660. 1993.
