Hammarbya paludosa (Bog Adder's-mouth)

Plant Info
Also known as:
Family:Orchidaceae (Orchid)
Life cycle:perennial
  • State Endangered
Habitat:part shade, shade; sphagnum hummocks in conifer swamps
Bloom season:July - August
Plant height:2 to 9 inches
Wetland Indicator Status:GP: OBL MW: OBL NCNE: OBL
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

[photo of flowers] A slender, spike-like raceme up to 3½ inches (9 cm) long of 2 to 30+ tiny green to greenish yellow flowers, evenly spaced at the top of the stem. The 3 sepals are each less than 1/8 inch (to 2.5 mm) long, elliptical to egg-shaped, pointed at the tip, 2 nearly erect at the top of the flower and 1 hanging straight down. The 3 petals are generally egg-shaped and about half the size of the sepals; the lip (at the top) typically has darker green veins and an abrupt point at the tip, the 2 lateral petals curve back behind the flower.

Leaves and stems: Leaf attachment: alternate Leaf attachment: basal Leaf type: simple

[photo of leaves] 2 to 5 leaves surround a thickened, bulb-like growth (pseudobulb) at the base of the stem. Leaves are 1/8 to 1 3/8 inch long (3 to 35 mm), up to ~½ inch (1 to 15 mm) wide, generally elliptical or widest above the middle, sheathing the stem. Stems are smooth and mostly erect.

Fruit: Fruit type: capsule/pod

[photo of developing fruit] Fruit is an elliptic, ascending capsule about 4 mm (1/6 inch) long.

[photo of propagules] Asexual reproduction also occurs, by way of propagules (gemmae) that sometimes form on leaf tips and eventually drop off, starting new plants.


Bog Adder's-mouth, formerly Malaxis paludosa, is considered to be one of the rarest orchids in North America, if not the rarest. According to the DNR, it was unknown in North America until it was discovered in Alaska in 1895 and wasn't known to be in the lower 48 states until it was found in Otter Tail County in 1904. Minnesota is still the only US state south of Canada where it is known to exist and was listed as an Endangered Species in 1984. Under the best conditions it is extremely difficult to spot; the small leaves are often hidden under the moss, leaving just the slender, green spike poking a few inches into the air.

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More photos

Photos by Peter M. Dziuk taken in Hubbard County. Photos by John Thayer taken in Itasca County.


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

Posted by: Jim Cramton - Bemidji
on: 2018-07-20 09:35:31

Whitfield, Rowe, Lee, and Smith 2015 gives Itasca and Koochiching counties as having populations of M. paludosa.

Posted by: K. Chayka
on: 2018-07-20 10:33:58

Jim, that may be true but MNTaxa has not been updated to reflect that nor are there any records for those counties in the Bell Herbarium, except for one undated entry for Koochiching that includes no info other than species name, so is unconfirmed. Those are the main sources of info for our distribution maps.

Posted by: Robert Freeman - Northern Minnesota
on: 2018-09-30 22:04:28

Jim, this plant is in both of the Counties you listed. I am a member of the North American Native Orchid Conference and we have been searching and studying this plant for the past 21 years. To date we have found at least 17 different locations for it all across Northern MN. Due to its small size it is often overlooked even by the trained and seasoned botanist. One must develop a schema for this plant as the odds of finding it will increase. Globally the plant is secure, and in time the US populations will be better documented. It is pollinated by a fungus gnat (Phronia digitata) The three listed Adder’s Mouth orchids in our state can be seen growing together on one hummock if you’re lucky to see it. Unfortunately, that is as close of a relationship those orchids will share as the correct name is now Hammarbya paludosa, the poor little fellow is not only the smallest Native Orchid, he is also the only representative in his Genus Hammarbya.

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