Northern Green Orchid is an erect native perennial. The stem, as can be seen in the large photo, is smooth but with vertical ridges on the upper part and into the flower raceme. Stem and inflorescence can be as short as 2 inches and as tall as 2 feet.
The leaves are strap-like, stalkless, with pointed tips as shown here, but sometimes rounded, and leaves are few to several, ascending and concentrated near the bottom of the stem, but are not basal. The leaves reduce to bracts in the inflorescence.
The inflorescence is a tall raceme, sometimes 8 to 10 inches long, and containing the flowers that open from the bottom of the raceme first.
The flowers of this orchid are not showy, being greenish or greenish-yellow, with up to 40 per plant, all stalkless, each subtended by an erect green bract. There are 3 sepals and 3 petals. Each flower has a hood on top formed by a sepal and two petals that are tucked in under the sepal. Below the hood, two yellow-green sepals spread out laterally and then a lower lip, the lance-shaped third petal, projects forward between them. You can see in the large photo below (at the top of the raceme) that, when just opening, this lower lip is flexed upward and touches the upper hood. None of the petals or sepals are fringed. This plant usually self-pollinates by the pollinia (discreet pollen masses, 2 in this species), which is housed at the inner top of the hood, rotating forward and downward making contact with the stigma, or else the pollen masses of the pollinia dissociate and fall to the stigma. Flowers in the Minnesota are scentless, but plants in more northern regions of North America may have scent.
Seed: Seeds form in an erect capsule.
Habitat: The habitat is bogs and wet meadows and moist woods, but it grows best in full sun. Northern Green Orchid has one of the most extensive ranges of any orchid.
Names: The genus name Platanthera is derived from the Greek platys, meaning 'broad or flat', and anthera for 'anther', combined - a flat or broad anther, which is the characteristic of this genus. The species name, aquilonis, is derived from aquilo, the north wind. This refers to the plants northern habitat.
Previous classifications have placed this species as Platanthera hyperborea and earlier as Habenaria hyperborea. The current classification is from 1999 and done by ‘Sheviak’, which refers to Charles J. Sheviak, (b. 1947) American botanist and expert on the Orchidaceae family.
Comparison: The closest look-a-like is the Tall Northern Bog Orchid, Platanthera huronensis, but as the name implies, it is usually taller, over 24 inches, flowers a little more whitish and scented. The flower parts have different shapes in P. huronensis and they do not auto-pollinate. Where the populations overlap and plants are 24 inches or shorter, one must make a careful study of the flowers to determine which species it is.
Above: 1st photo - Note the winged ridges of the stem. 2nd photo - A plant with the raceme just emerging.
Below: Flower Arrangement. 1st photo - Note on younger flowers, toward the top of the raceme, the lower lip is bent upward touching the upper hood. 3rd photo - The two flaring laterals are sepals; the third petal forms the projecting tongue.
Below: 1st & 2nd photo - Stem and inflorescence can be as short as 2 inches and as tall as 2 feet. 3rd photo - An example of the varying heights of the stems.
Notes: Eloise Butler first noted planting Northern Green Orchid on June 16, 1915 with plants obtained from the 'Big Bog' at Lake Minnetonka (MN). In 1916 she discovered it growing in another part of the wetland, thus it was indigenous. She added more on Aug. 12, 1918 with plants from near Lake Margaret in Pequot, MN and more plantings in 1921, '22, '24, '28, '30, and '31. Martha Crone reported planting it on Aug. 1, 1933 with specimens obtained "near Duluth". She added more in 1947, '49, '50, and '53. Both she and Eloise Butler used the earlier scientific name Habenaria hyperborea, and a common name of Leafy Green Orchis. These have now been classified under Platanthera aquilonis. Martha reported it in the Garden on her 1951 Garden Census. It died out some years later. In North America the plant is found all across Canada and the U.S. states from the east coast to the west coast north of a Kansas - Virginia east/west line. West of the Great Plains the habitat extends down the western mountain ranges to the Mexican border.
Platanthera aquilonis is one of 11 species of Platanthera native to Minnesota, 8 of which are found in Hennepin County where the Garden is located.
For an article on all the orchids in the Garden, past and present, see this article.
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"