Platanthera flava var. herbiola (Tubercled Rein Orchid)

Plant Info
Also known as: Pale Green Orchid, Pale Green Orchis
Family:Orchidaceae (Orchid)
Life cycle:perennial
  • State Threatened
Habitat:part shade, sun; moist sedge meadows, wetland edges, floodplains
Bloom season:July
Plant height:7 to 18 inches
Wetland Indicator Status:GP: FACW MW: FACW NCNE: FACW
MN county distribution (click map to enlarge):Minnesota county distribution map
National distribution (click map to enlarge):National distribution map

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Detailed Information

Flower: Flower shape: irregular Cluster type: raceme Cluster type: spike

[photo of flowers] Spike-like raceme of irregular pale greenish ¼-inch flowers. Sepals and petals are similar; an upper sepal and 2 petals form a hood above, 2 side sepals opened out broadly. The lower lip is broad, with squared sides, a round tip, 2 small side lobes at the base, and near the center of the base a small bump (the tubercle) that blocks insects from entering up the middle, forcing them to enter from the sides. A curved stout spur is below. The flower spike is shorter and more tightly packed in sunny locations, more stretched in the shade.

Leaves and stem: Leaf attachment: alternate Leaf type: simple

[photo of leaves] There are 2 to 3 principal leaves, up to 6 inches long, ¾ inch wide, lanceolate to elliptical, alternately attached, with pointed tips and sheathing at the base. A few short bract-like leaves are on the upper stem. The stem is smooth. Plants are stouter in open sun than in shadier locations.


Minnesota is on the northwest edge of this species' range. Rare scattered populations are on the Anoka Sandplain with a few central and southeast Minnesota populations. According to the DNR, much of its habitat is being destroyed by development, mostly around the Metro area. The remaining populations are also threatened by invasive species, woody plants like buckthorn in particular, which kill off the plants by providing too much shade. Tubercled Rein Orchid was added to the Minnesota State Endangered Species list in 1984 but downgraded to Threatened in 2013 after a number of new populations were discovered. This species sometimes goes by Habenaria flava (as in Newcomb's and Peterson's field guides), but genus Habenaria is now widely considered restricted to the tropical species and Platanthera the temperate zone species. Another variety P. flava var. flava, is mostly limited to the southeast U.S. and does not grow in Minnesota.

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More photos

Photos courtesy Peter M. Dziuk taken in Anoka county


Have you seen this plant in Minnesota, or have any other comments about it?

Posted by: Jason Husveth - All over MN
on: 2011-06-15 21:10:52

Peter's photos, I believe, are not from a "Cedar Bog" in Anoka County. Most likely, they are from a rich fen dominated by several sedges and bog birch, but no white cedar or anything that could be easily confused with a cedar. Also, photo 2's caption is more accurately described as "tuberceled rein orchid co-existing with glossy buckthorn" which is the case at Pioneer Park, where the picture is most likely from. Also, the USDA's county distribution map for this species, oddly enough, does not include Anoka County, which is currently the epi-center for this species' distribution in the state of Minnesota. Regards, Jason Husveth

Posted by: K. Chayka
on: 2011-06-16 14:20:51

Jason, you are correct--it is not a cedar bog, but a fen. We are not convinced, however, that the "co-existence" with glossy buckthorn would be possible without your intense management of that land. Also, the USDA maps are woefully out of date and there does not appear any way to correct them, so we started making our own maps earlier this year. Eventually all species will have new maps.

Posted by: Mike Humrickhouse - Brainerd
on: 2021-07-01 08:57:24

To your knowledge, is Tubercled Rein Orchid available commercially?

Posted by: K. Chayka
on: 2021-07-01 10:47:59

Mike, I do not believe it is available in the commercial orchid trade.

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