Malaxis unifolia - Michx.
Green Adder's-mouth Orchid
Other Common Names: green adder's-mouth orchid
Taxonomic Status: Accepted
Related ITIS Name(s): Malaxis unifolia Michx. (TSN 43647)
Unique Identifier: ELEMENT_GLOBAL.2.157204
Element Code: PMORC1R0A0
Informal Taxonomy: Plants, Vascular - Flowering Plants - Orchid Family
Kingdom Phylum Class Order Family Genus
Plantae Anthophyta Monocotyledoneae Orchidales Orchidaceae Malaxis
Check this box to expand all report sections:
Concept Reference
Concept Reference: Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
Concept Reference Code: B94KAR01HQUS
Name Used in Concept Reference: Malaxis unifolia
Conservation Status

NatureServe Status

Global Status: G5
Global Status Last Reviewed: 13May2016
Global Status Last Changed: 16Apr1984
Ranking Methodology Used: Ranked by inspection
Rounded Global Status: G5 - Secure
Nation: United States
National Status: N5
Nation: Canada
National Status: N5 (03Nov2017)

U.S. & Canada State/Province Status
Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
United States Alabama (SNR), Arkansas (SNR), Connecticut (S1), Delaware (S1), District of Columbia (SNR), Florida (S3), Georgia (S4), Illinois (S1), Indiana (S1), Iowa (SX), Kansas (S1), Kentucky (S4?), Louisiana (S4), Maine (SNR), Maryland (S1S3), Massachusetts (S2?), Michigan (SNR), Minnesota (SNR), Mississippi (SNR), Missouri (S3), New Hampshire (S3), New Jersey (SH), New York (S4), North Carolina (S4), Ohio (S3), Oklahoma (S1), Pennsylvania (SNR), Rhode Island (S1), South Carolina (SNR), Tennessee (SNR), Texas (SNR), Vermont (S2), Virginia (S4), West Virginia (S4), Wisconsin (SNR)
Canada Labrador (S3), Manitoba (S2?), New Brunswick (S4), Newfoundland Island (S3), Nova Scotia (S4S5), Ontario (S4S5), Prince Edward Island (S3), Quebec (S4S5), Saskatchewan (SNR)

Other Statuses

NatureServe Global Conservation Status Factors

Other NatureServe Conservation Status Information

U.S. States and Canadian Provinces

Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
Color legend for Distribution Map

U.S. & Canada State/Province Distribution
United States AL, AR, CT, DC, DE, FL, GA, IAextirpated, IL, IN, KS, KY, LA, MA, MD, ME, MI, MN, MO, MS, NC, NH, NJ, NY, OH, OK, PA, RI, SC, TN, TX, VA, VT, WI, WV
Canada LB, MB, NB, NF, NS, ON, PE, QC, SK

Range Map
No map available.

U.S. Distribution by County Help
State County Name (FIPS Code)
CT Hartford (09003)*, New Haven (09009)*, New London (09011), Tolland (09013)*, Windham (09015)
DE New Castle (10003), Sussex (10005)
FL Alachua (12001), Escambia (12033)*, Gadsden (12039), Hernando (12053), Jackson (12063), Leon (12073), Liberty (12077), Okaloosa (12091), Walton (12131), Washington (12133)
IA Boone (19015)*, Iowa (19095)*, Johnson (19103)*, Muscatine (19139)*, Story (19169)*, Tama (19171)*, Winneshiek (19191)*
IN Elkhart (18039), Kosciusko (18085)*, La Porte (18091)*, Lake (18089), Monroe (18105), Noble (18113)*, St. Joseph (18141)
KS Cherokee (20021), Douglas (20045)
MA Berkshire (25003), Bristol (25005)*, Dukes (25007)*, Essex (25009), Franklin (25011)*, Norfolk (25021)*, Suffolk (25025)*, Worcester (25027)
MO Butler (29023)*, Carter (29035), Crawford (29055), Dent (29065), Douglas (29067)*, Greene (29077)*, Howell (29091), Iron (29093), Jefferson (29099)*, Oregon (29149), Ozark (29153)*, Phelps (29161), Reynolds (29179), Shannon (29203), St. Louis (29189)*, St. Louis (city) (29510)*, Ste. Genevieve (29186), Texas (29215), Washington (29221), Wayne (29223)*
NH Belknap (33001)*, Carroll (33003), Cheshire (33005)*, Coos (33007), Grafton (33009), Hillsborough (33011)*, Merrimack (33013), Rockingham (33015), Strafford (33017), Sullivan (33019)*
NJ Atlantic (34001)*, Bergen (34003)*, Burlington (34005)*, Camden (34007)*, Essex (34013)*, Gloucester (34015)*, Hudson (34017)*, Hunterdon (34019)*, Middlesex (34023)*, Monmouth (34025)*, Morris (34027)*, Ocean (34029)*, Passaic (34031)*, Salem (34033)*, Somerset (34035)*, Sussex (34037)*, Union (34039)*
OH Athens (39009), Fairfield (39045), Gallia (39053)*, Hocking (39073), Knox (39083), Lawrence (39087), Meigs (39105)*, Perry (39127), Pike (39131), Ross (39141), Scioto (39145), Vinton (39163), Washington (39167)
OK Le Flore (40079), McCurtain (40089)
RI Kent (44003)*, Providence (44007)*, Washington (44009)
VT Addison (50001), Caledonia (50005), Chittenden (50007), Essex (50009), Grand Isle (50013), Lamoille (50015), Orange (50017), Orleans (50019), Rutland (50021), Washington (50023), Windsor (50027)
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
01 Upper Androscoggin (01040001)+*, Lower Androscoggin (01040002)+*, Saco (01060002)+, Piscataqua-Salmon Falls (01060003)+, Pemigewasset (01070001)+, Merrimack (01070002)+, Contoocook (01070003)+*, Merrimack (01070006)+, Upper Connecticut (01080101)+, Passumpsic (01080102)+, Waits (01080103)+, Upper Connecticut-Mascoma (01080104)+*, White (01080105)+, Black-Ottauquechee (01080106)+, Middle Connecticut (01080201)+*, Miller (01080202)+*, Lower Connecticut (01080205)+*, Charles (01090001)+*, Cape Cod (01090002)+*, Blackstone (01090003)+, Narragansett (01090004)+*, Pawcatuck-Wood (01090005)+, Quinebaug (01100001)+, Shetucket (01100002)+, Quinnipiac (01100004)+*, Housatonic (01100005)+*
02 Hudson-Hoosic (02020003)+, Middle Hudson (02020006)+*, Rondout (02020007)+*, Lower Hudson (02030101)+*, Hackensack-Passaic (02030103)+*, Sandy Hook-Staten Island (02030104)+*, Raritan (02030105)+*, Middle Delaware-Mongaup-Brodhead (02040104)+*, Middle Delaware-Musconetcong (02040105)+*, Lower Delaware (02040202)+*, Cohansey-Maurice (02040206)+*, Broadkill-Smyrna (02040207)+, Mullica-Toms (02040301)+*, Great Egg Harbor (02040302)+*, Western Lower Delmarva (02080109)+
03 Oklawaha (03080102)+, Crystal-Pithlachascotee (03100207)+, Santa Fe (03110206)+*, Apalachee Bay-St. Marks (03120001)+, Lower Ochlockonee (03120003)+, Lower Chattahoochee (03130004)+, Apalachicola (03130011)+, Chipola (03130012)+, St. Andrew-St. Joseph Bays (03140101)+, Choctawhatchee Bay (03140102)+, Perdido (03140106)+*
04 Little Calumet-Galien (04040001)+*, St. Joseph (04050001)+, Mettawee River (04150401)+, Otter Creek (04150402)+, Winooski River (04150403)+, Lamoille River (04150405)+, Lake Champlain (04150408)+, St. Francois River (04150500)+
05 Little Muskingum-Middle Island (05030201)+, Upper Ohio-Shade (05030202)+*, Hocking (05030204)+, Mohican (05040002)+, Lower Scioto (05060002)+, Raccoon-Symmes (05090101)+, Little Scioto-Tygarts (05090103)+, Ohio Brush-Whiteoak (05090201)+, Tippecanoe (05120106)+*, Lower White (05120202)+, Lower East Fork White (05120208)+*
07 Root (07040008)+*, Upper Iowa (07060002)+*, Copperas-Duck (07080101)+*, South Skunk (07080105)+*, Lower Cedar (07080206)+*, Middle Iowa (07080208)+*, Lower Iowa (07080209)+*, Kankakee (07120001)+, Chicago (07120003)+, Cahokia-Joachim (07140101)+, Meramec (07140102)+, Big (07140104)+, Upper Mississippi-Cape Girardeau (07140105)+
08 Upper St. Francis (08020202)+*
10 Lower Kansas (10270104)+, Sac (10290106)+*, Big Piney (10290202)+, Lower Missouri (10300200)+*
11 North Fork White (11010006)+, Upper Black (11010007)+, Current (11010008)+, Spring (11010010)+*, Eleven Point (11010011)+, Spring (11070207)+, Kiamichi (11140105)+, Pecan-Waterhole (11140106)+, Upper Little (11140107)+, Mountain Fork (11140108)+
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
Ecology & Life History Not yet assessed
Economic Attributes Not yet assessed
Management Summary Not yet assessed
Population/Occurrence Delineation Not yet assessed
Population/Occurrence Viability
U.S. Invasive Species Impact Rank (I-Rank) Not yet assessed

Botanical data developed by NatureServe and its network of natural heritage programs (see Local Programs), The North Carolina Botanical Garden, and other contributors and cooperators (see Sources).

  • Aldrich, James R., et. al. 1986. The Discovery of Native Rare Vascular Plants in Northern Indiana. Indiana Academy of Science 95:421-428.

  • Bowles, Marlin. 1990. Report on the Status of Endangered and Threatened Plants of the Indiana Dunes National Lakeshore; Monitoring of Species New to the Lakeshore and Re-monitoring of Selected Species. To Indiana Dunes National Lakeshore.

  • Bruce-Grey Plant Committee (Owen Sound Field Naturalists). [1997]. A Guide to the Orchids of Bruce and Grey Counties, Ontario. Stan Brown Printers Limited, Owen Sound, Ontario. 105 pp.

  • Brunton, D.F., and W.J. Crins. 1992. Checklist of the Vascular Plants of Algonquin Provincial Park (Revised). Algonquin Park Technical Bulletin No. 4. The Friends of Algonquin Park, Whitney, Ontario in cooperation with the Ontario Ministry of Natural Resources.

  • Case, F.W., Jr. 1987. Orchids of the Western Great Lakes Region. Revised Edition. Bulletin 48, Cranbrook Institute of Science, Bloomfield Hills, Michigan. 251 pp.

  • Catling, P.M. 1991. Systematics of Malaxis bayardii and M. Unifolia. Lindleyana 6(1): 3-23.

  • Deam, C. C. 1940. Flora of Indiana. Division of Forestry, Dept. of Conservation, Indianapolis, Indiana. 1236 pp.

  • Flora of North America Editorial Committee. 2002a. Flora of North America North of Mexico. Vol. 26. Magnoliophyta: Liliidae: Liliales and Orchidales. Oxford Univ. Press, New York. xxvi + 723 pp.

  • General Status 2015, Environment Canada. 2015. Manitoba vascular plant species list and proposed ranks and rank factors proposed by contractor (Diana Sawatzky).

  • Herbarium, Department of Botany, University of Manitoba, Winnipeg, Manitoba, Canada.

  • Herbarium, Museum of Man and Nature, 190 Rupert Avenue, Winnipeg, Manitoba.

  • Homoya, M.A. 1993. Orchids of Indiana. Indiana Academy of Science, Indianapolis, Indiana. 276 pp.

  • Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.

  • Klick, Ken, Kosak, E. McCloskey, T. Post. 1987. Malaxis unifolia: Hoosier Prairie. Location Map of Occurrences. 2 pp.

  • Luer, C.A. 1975. The native orchids of the United States and Canada excluding Florida. The New York Botanical Garden. 361 pp.

  • Manitoba Conservation Data Centre. 2018. Vascular Plant Species ranking forms from initial CDC ranking.

  • Morris, F. and E.A. Eames. 1929. Our Wild Orchids. Charles Scribner's Sons, New York. 464 pp.

  • Reddoch, J.M. and A.H. Reddoch. 1997. The orchids in the Ottawa District: floristics, phytogeography, population studies and historical review. Canadian Field-Naturalist 111(1):1-185.

  • Skelton, E.G. and E.W. Skelton. 1991. Haliburton Flora: An Annotated List of the Vascular Plants of the County of Haliburton, Ontario.. Miscellaneous Publications, Royal Ontario Museum, Life Sciences, Toronto. 142 pp.

  • Swink, F., and G. Wilhelm. 1994. Plants of the Chicago Region. Morton Arboretum. Lisle, Illinois.

  • Walshe, S. 1980. Plants of Quetico and the Ontario Shield. Quetico Foundation, University of Toronto Press, Toronto, Ontario. 152 pp.

  • White, D.J. and K.L. Johnson. 1980. The Rare Vascular Plants of Manitoba. National Museums of Canada Syllogeus no. 27.

  • Whiting, R.E. and P.M. Catling. 1986. Orchids of Ontario: An Illustrated Guide. The CanaColl Foundation, Ottawa, Ontario. xii + 169 pp.

Use Guidelines & Citation

Use Guidelines and Citation

The Small Print: Trademark, Copyright, Citation Guidelines, Restrictions on Use, and Information Disclaimer.

Note: All species and ecological community data presented in NatureServe Explorer at were updated to be current with NatureServe's central databases as of March 2019.
Note: This report was printed on

Trademark Notice: "NatureServe", NatureServe Explorer, The NatureServe logo, and all other names of NatureServe programs referenced herein are trademarks of NatureServe. Any other product or company names mentioned herein are the trademarks of their respective owners.

Copyright Notice: Copyright © 2019 NatureServe, 2511 Richmond (Jefferson Davis) Highway, Suite 930, Arlington, VA 22202, U.S.A. All Rights Reserved. Each document delivered from this server or web site may contain other proprietary notices and copyright information relating to that document. The following citation should be used in any published materials which reference the web site.

Citation for data on website including State Distribution, Watershed, and Reptile Range maps:
NatureServe. 2019. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Available (Accessed:

Citation for Bird Range Maps of North America:
Ridgely, R.S., T.F. Allnutt, T. Brooks, D.K. McNicol, D.W. Mehlman, B.E. Young, and J.R. Zook. 2003. Digital Distribution Maps of the Birds of the Western Hemisphere, version 1.0. NatureServe, Arlington, Virginia, USA.

Acknowledgement Statement for Bird Range Maps of North America:
"Data provided by NatureServe in collaboration with Robert Ridgely, James Zook, The Nature Conservancy - Migratory Bird Program, Conservation International - CABS, World Wildlife Fund - US, and Environment Canada - WILDSPACE."

Citation for Mammal Range Maps of North America:
Patterson, B.D., G. Ceballos, W. Sechrest, M.F. Tognelli, T. Brooks, L. Luna, P. Ortega, I. Salazar, and B.E. Young. 2003. Digital Distribution Maps of the Mammals of the Western Hemisphere, version 1.0. NatureServe, Arlington, Virginia, USA.

Acknowledgement Statement for Mammal Range Maps of North America:
"Data provided by NatureServe in collaboration with Bruce Patterson, Wes Sechrest, Marcelo Tognelli, Gerardo Ceballos, The Nature Conservancy-Migratory Bird Program, Conservation International-CABS, World Wildlife Fund-US, and Environment Canada-WILDSPACE."

Citation for Amphibian Range Maps of the Western Hemisphere:
IUCN, Conservation International, and NatureServe. 2004. Global Amphibian Assessment. IUCN, Conservation International, and NatureServe, Washington, DC and Arlington, Virginia, USA.

Acknowledgement Statement for Amphibian Range Maps of the Western Hemisphere:
"Data developed as part of the Global Amphibian Assessment and provided by IUCN-World Conservation Union, Conservation International and NatureServe."

NOTE: Full metadata for the Bird Range Maps of North America is available at:

Full metadata for the Mammal Range Maps of North America is available at:

Restrictions on Use: Permission to use, copy and distribute documents delivered from this server is hereby granted under the following conditions:
  1. The above copyright notice must appear in all copies;
  2. Any use of the documents available from this server must be for informational purposes only and in no instance for commercial purposes;
  3. Some data may be downloaded to files and altered in format for analytical purposes, however the data should still be referenced using the citation above;
  4. No graphics available from this server can be used, copied or distributed separate from the accompanying text. Any rights not expressly granted herein are reserved by NatureServe. Nothing contained herein shall be construed as conferring by implication, estoppel, or otherwise any license or right under any trademark of NatureServe. No trademark owned by NatureServe may be used in advertising or promotion pertaining to the distribution of documents delivered from this server without specific advance permission from NatureServe. Except as expressly provided above, nothing contained herein shall be construed as conferring any license or right under any NatureServe copyright.
Information Warranty Disclaimer: All documents and related graphics provided by this server and any other documents which are referenced by or linked to this server are provided "as is" without warranty as to the currentness, completeness, or accuracy of any specific data. NatureServe hereby disclaims all warranties and conditions with regard to any documents provided by this server or any other documents which are referenced by or linked to this server, including but not limited to all implied warranties and conditions of merchantibility, fitness for a particular purpose, and non-infringement. NatureServe makes no representations about the suitability of the information delivered from this server or any other documents that are referenced to or linked to this server. In no event shall NatureServe be liable for any special, indirect, incidental, consequential damages, or for damages of any kind arising out of or in connection with the use or performance of information contained in any documents provided by this server or in any other documents which are referenced by or linked to this server, under any theory of liability used. NatureServe may update or make changes to the documents provided by this server at any time without notice; however, NatureServe makes no commitment to update the information contained herein. Since the data in the central databases are continually being updated, it is advisable to refresh data retrieved at least once a year after its receipt. The data provided is for planning, assessment, and informational purposes. Site specific projects or activities should be reviewed for potential environmental impacts with appropriate regulatory agencies. If ground-disturbing activities are proposed on a site, the appropriate state natural heritage program(s) or conservation data center can be contacted for a site-specific review of the project area (see Visit Local Programs).

Feedback Request: NatureServe encourages users to let us know of any errors or significant omissions that you find in the data through (see Contact Us). Your comments will be very valuable in improving the overall quality of our databases for the benefit of all users.