- Scientific name: Platanthera huronensis Lindl.
- Species of Greatest Conservation Need (MA State Wildlife Action Plan)
Description
Northern Green Orchid (Platanthera huronensis). Photo credit: Welby R. Smith
he northern green orchid, Platanthera huronensis, is widespread and rare across northern New England, but only verified in Berkshire county in Massachusetts.Much is still to be learned about this species as it was only fairly recently recognized as a species by the taxonomic splitting of another species that is more widespread and more familiar to experienced botanists and wildflower enthusiasts: the northern bog orchid (Platanthera hyperborea). It was discovered that P. hyperborea is actually three separate species. The original name, P. hyperborea (L.) Lindl., now refers to a species only documented from Greenland and Iceland. The other two species became the northern green orchid (P. huronensis) and the north wind orchid (Platanthera aquilonis) Sheviak. Complications have arisen as these two species can sometimes not be differentiated in herbarium specimens, making the known distribution subject to some mystery. Even in living specimens, it can be difficult, if not impossible, to distinguish between the two unless they are flowering, when the fragrance of the flowers can be checked. The northern green orchid is quite fragrant—sometimes described as sweet and pungent—whereas the north wind orchid is scentless. It is self-pollinating, so it does not need to attract pollinators with a pleasing aroma. Other differences between the two are found in the minute flower structures, which require a 10x hand lens to see.
The northern green orchid is thought to have arisen as a tetraploid (four sets of chromosomes) cross of two diploid species: the northern white orchid (Platanthera dilatata) and the north wind orchid (P. aquilonis).
The northern green orchid varies from 25 cm (9.8 in) in height to as tall as 105 cm (41 in). There are as many as seven green leaves scattered along the upright stem. The leaves are narrowly elliptic with the longest approximately 30 cm (11.8 in) long and about 6 cm (2.4 in) in width. The stem holds as many as 60 whitish-green flowers in a raceme or spike above the leaves. Individually, the flowers are rather small—about 1 cm (0.4 in) across—with a 5–12 mm (0.2–0.5 in) long lip or labellum. The sepals are slightly greener than the petals. The uppermost sepal forms a bit of a hood over the flower. Like many of this genus, the flowers have a nectar spur that curves in an arch toward the front of the flower. The flower is attached to the stem with a rather thick stalk that is the ovary. Right at the base of the stalk is a short leafy upright bract that extends up to about the midpoint of the flower itself.
The northern green orchid looks almost identical to the north wind orchid (Platanthera aquilonis). In the field, fragrance and flower color are useful to distinguish the two, with P. aquilonis having no smell and a green to yellow-green cast to the labellum (lip) of the flower, and P. huronensis having a sweet, distinct fragrance and a more white-green cast. The nectar spur tends to be longer in P. huronensis, ranging from 4–12 mm (0.2–0.5 in), and from 2–5 mm (0.08–0.2 in) in P. aquilonis.
Life cycle and behavior
Northern green orchid flowers from late June to mid-July. It is not known what species of insects pollinate this orchid, but small insects, including mosquitoes, may be its pollinators. It is a perennial species, which may not produce a flowering stem every year. To germinate, the seeds require a mycorrhizae fungus to assist by supplying food and water. The relationship with the fungus is likely to last the plant’s entire life.
Population status
The northern green orchid is a Species of Greatest Conservation Need and is maintained on the Massachusetts plant watch list. It is only known from Berkshire county. Most of what was previously documented as Platanthera hyperborea was determined to be P. aquilonis, and not P. huronensis. Natural Heritage and Endangered Species Program currently knows of only 3 populations.
Distribution and abundance
The northern green orchid is found throughout the northern latitudes from Labrador south to New Jersey, west to Alaska (except in the prairie states from Saskatchewan south to Texas). It is also found in Wyoming, Colorado, and New Mexico.
Distribution in Massachusetts. 1999-2024. Based on records in the Natural Heritage Database
Habitat
The northern green orchid is found most often in wetlands, including ditches, shorelines, small pools, wet meadows, and marshes, which have a higher pH.
Healthy habitats are vital for supporting native wildlife and plants. Explore habitats and learn about conservation and restoration in Massachusetts.
Threats
This species is generally found in wetlands in New England. Disturbances to the natural hydrological regime will threaten this species, as will climate change induced or natural drought cycles. Additionally, deer will eat the plant, and invasive species at a site, such as reed canary grass and giant reed grass, can crowd out this plant.
Conservation
Because of the recent taxonomic changes with this species and difficulties with herbarium specimens, much more field work is needed to identify locations for the northern green orchid. In addition, current sites should be protected from development, and habitat management should include control of invasive species and herbivores.
References
Haines, A. 2011. New England Wild Flower Society's Flora Novae Angliae: A Manual for the Identification of Native and Naturalized Higher Vascular Plants of New England. Yale University Press.
NatureServe. 2025. NatureServe Network Biodiversity Location Data accessed through NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org/. Accessed: 5/15/2025.
North American Orchid Conservation Center, c/o Smithsonian Environmental Research Center. https://goorchids.northamericanorchidcenter.org/species/platanthera/huronensis/ Accessed 5/15/2025.
Sheviak, C. J. 1999. The identities of Platanthera hyperborea and P. huronensis, with the description of a new species from North America. Lindleyana, 14(4), 193-203.
Smith, W. R. 2012. Native Orchids of Minnesota. U of Minnesota Press. 286 pp.
Contact
| Date published: | May 15, 2025 |
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