Micranthemum micranthemoides - (Nutt.) Wettst.
Nuttall's Micranthemum
Other English Common Names: Nuttall's Mudflower
Other Common Names: Nuttall's mudflower
Taxonomic Status: Accepted
Related ITIS Name(s): Micranthemum micranthemoides (Nutt.) Wettst. (TSN 33229)
Unique Identifier: ELEMENT_GLOBAL.2.130713
Element Code: PDSCR19020
Informal Taxonomy: Plants, Vascular - Flowering Plants - Figwort Family
 
Kingdom Phylum Class Order Family Genus
Plantae Anthophyta Dicotyledoneae Scrophulariales Scrophulariaceae Micranthemum
Check this box to expand all report sections:
Concept Reference
Help
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: Micranthemum micranthemoides
Taxonomic Comments: Distinct species, sometimes placed in the genus Hemianthus as Hemianthus micranthemoides. The name Micranthemum micranthemoides (or the equivalent Hemianthus micranthemoides) was formerly applied to a broader species concept that included plants not only of the northeastern United States, but also other plants of the southeastern U.S. and the West Indies that botanists now generally consider distinct (such as M. glomeratus of Florida).
Conservation Status
Help

NatureServe Status

Global Status: GH
Global Status Last Reviewed: 09Sep1995
Global Status Last Changed: 22Jun1983
Rounded Global Status: GH - Possibly Extinct
Reasons: Last seen anywhere on September 13, 1941, this species was known only from freshwater tidal shores of several northeastern and mid-Atlantic rivers, including the Hudson, Delaware, Potomac, and Anacostia. Suitable habitat still exists, particularly in Virginia, Maryland, and New Jersey, but this species has not been relocated despite repeated searches.
Nation: United States
National Status: NH

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 Delaware (SX), District of Columbia (SH), Maryland (SH), New Jersey (SH), New York (SX), Pennsylvania (SX), Virginia (SH)

Other Statuses

NatureServe Global Conservation Status Factors

Range Extent Comments: Historically known from New York to Virginia: Mainly in the drainage of Delaware and Chesapeake Bays in the embayed section of the Atlantic Coastal Plain (Delaware, Pocomoke, Wicomico, Potomac, Anacostia, and Chickahominy rivers), and also on the Raritan and the middle Hudson River. known only from the freshwater-intertidal portions of these rivers; erroneously considered by Fassett (1928) to occur as "outposts" on estuaries with its main range said to be "muddy banks from New Jersey to Florida" citing Small (1913), but as currently treated, known only from New York to Virginia, and only in freshwater-estuarine habitats.

Number of Occurrences: 0 - 5
Number of Occurrences Comments: Not definitely seen anywhere since Sept. 13, 1941.

Population Size Comments: No individuals known; was formerly reported as locally abundant at some sites (e.g., tidal flats along Delaware River).

Number of Occurrences with Good Viability/Integrity: None (zero)

Overall Threat Impact: High - medium
Overall Threat Impact Comments: Habitat continues to be vulnerable to shore development, bulkheading, and channelization. Increased siltation rates following European settlement and land-clearing has probably affected most sites. Sea-level rise may be an additional threatening factor, both inundating any existing seedbanks and also leading to saltwater intrusion upstream into areas formerly fresh.

Short-term Trend: Decline of >30%
Short-term Trend Comments: Was known from at least three rivers in the 1930's, but last seen anywhere in 1941.

Intrinsic Vulnerability Comments: Specialist of narrow niche, vulnerable to erosion, extreme siltation, vegetational succession, and saltwater intrusion.

Other NatureServe Conservation Status Information

Distribution
Help
Global Range: Historically known from New York to Virginia: Mainly in the drainage of Delaware and Chesapeake Bays in the embayed section of the Atlantic Coastal Plain (Delaware, Pocomoke, Wicomico, Potomac, Anacostia, and Chickahominy rivers), and also on the Raritan and the middle Hudson River. known only from the freshwater-intertidal portions of these rivers; erroneously considered by Fassett (1928) to occur as "outposts" on estuaries with its main range said to be "muddy banks from New Jersey to Florida" citing Small (1913), but as currently treated, known only from New York to Virginia, and only in freshwater-estuarine habitats.

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 DC, DEextirpated, MD, NJ, NYextirpated, PAextirpated, VA

Range Map
No map available.


U.S. Distribution by County Help
State County Name (FIPS Code)
MD Caroline (24011)*, Dorchester (24019)*, Prince Georges (24033)*, Wicomico (24045)*, Worcester (24047)*
NJ Burlington (34005)*, Camden (34007)*, Gloucester (34015)*, Middlesex (34023)*
NY Dutchess (36027)*
PA Bucks (42017)*, Philadelphia (42101)*
VA Alexandria (City) (51510)*, Charles City (51036)*, Fairfax (51059)*, New Kent (51127)*
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
02 Middle Hudson (02020006)+*, Raritan (02030105)+*, Crosswicks-Neshaminy (02040201)+*, Lower Delaware (02040202)+*, Schuylkill (02040203)+*, Choptank (02060005)+*, Middle Potomac-Anacostia-Occoquan (02070010)+*, Western Lower Delmarva (02080109)+*, Eastern Lower Delmarva (02080110)+*, Pokomoke-Western Lower Delmarva (02080111)+*, Lower James (02080206)+*
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
Ecology & Life History
Help
Basic Description: A decumbent annual herb, < 6 cm tall, with oval or spatula-shaped leaves. Inconspicuous white flowers, borne in the axils of the leaves, bloom August-October. The small flowers of this speices are self-fertilizing and remain closed throughout their "blooming" period. There are several look-alike plants with which the species can be confused.
Technical Description: "Small, creeping glabrous annual herbs with many ascending branches often rooted at the nodes with fibrous roots; leaves numerous, opposite or whorled, elliptic to obovate-spatulate or rarely oval, 3-5 mm long, up to 4 mm wide, entire, obtuse, obscurely 3-veined, sessile; pedicels mostly solitary at the nodes, bractless, up to 1 mm long and straight at anthesis, becoming pyriform in fruit, the lobes seperate to the middle except on the lower side where cleft to the base; corolla white, the upper lip of 2 petals lacking, the lower lip 3-lobed with the median, incurved lobe about twice the length of the other two, this about 2 mm long; stamens 2, these, the lower pair, inserted on the corolla throat, the filaments with a projecting glandular, mostly basal appendage, the anthers 2-locular, didynamous; style short, deeply bifid; fruits thin, globular capsules 1.5 mm in diameter, with an evanescent partition, several-seeded." (Unpublished material in TNC files)
Diagnostic Characteristics: Branches ascending at the tips (resembling chickweed), often rooting at the notes. Leaves opposite or whorled, entire, elliptic to obovate-spathulate, sessile, obscurely 3-veined, acute (or even obtuse) rather than acuminate at the base. Flowers and fruits on a 1mm pedicel, not sessile. ; leaves obovate-spatulate or oval; pedicels about the length of the calyx which is split down the anterior side to the base while umbrosum has deeply and equally cleft calyx. The calyx is campanulate and 4-toothed. Vegetative plants of Micranthemum micranthemoides can be easily confused with plants of Elatine sp., which however spread flat on the substrate, have single-veined leaves that are more acuminate at the base, and sessile flowers or fruits. Young plants or young shoots of Hypericum also resemble Micranthemum superficially. Lindernia sp. can also resemble it. (Fernald, 1950; Gray Herbarium files; L.E. Morse, observations from specimens).
Duration: ANNUAL
Reproduction Comments: Morphology suggests partial cleistogamy.
Ecology Comments: Delicate nature suggests the plant is intolerant of heavy disturbance (although requiring slight recurrent disturbance to keep habitat open), and is intolerant of shade. Distribution is restricted to freshwater estuarine shores, suggesting intolerance to significant salinity.
Estuarine Habitat(s): River mouth/tidal river, Tidal flat/shore
Riverine Habitat(s): BIG RIVER, Low gradient, MEDIUM RIVER
Habitat Comments: Sandy to gravelly Coastal Plain rivershores in the relatively small freshwater zone that is influenced by ocean tides. These rivers are medium-sized to large with 0.6-1 m of tide. Fassett (1928) and Ferren and Schuyler (1980) provide further discussion of this habitat.
Economic Attributes
Help
Economic Comments: Reported occasionally as an aquarium plant, but identification of such material unclear.
Management Summary Not yet assessed
Help
Population/Occurrence Delineation Not yet assessed
Help
Population/Occurrence Viability
Help
U.S. Invasive Species Impact Rank (I-Rank) Not yet assessed
Help
Authors/Contributors
Help
NatureServe Conservation Status Factors Edition Date: 13Sep1995
NatureServe Conservation Status Factors Author: Morse, L.E., & E. Roth (1987), rev. L. Morse (1995), rev. Morse/Maybury/McAvoy/S. Young (1997)
Element Ecology & Life History Edition Date: 11Sep1995
Element Ecology & Life History Author(s): MORSE, LARRY E.

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).

References
Help
  • Fassett, N.C. 1928. The vegetation of the estuaries of northeastern North America. Proceedings Boston Society of Natural History 30: 75-130, pl. 6-15.

  • Fernald, M. L. 1950. Gray's manual of botany. 8th edition. Corrected printing (1970). D. Van Nostrand Company, New York. 1632 pp.

  • Fernald, M.L. 1950. Gray's manual of botany. 8th edition. D. Van Nostrand, New York. 1632 pp.

  • Ferren, W.R., Jr., and A.E. Schuyler. 1980. Intertidal vascular plants of river systems near Philadelphia. Proceedings Academy Natural Sciences Philadelphia 132: 86-120.

  • Gleason, H.A. 1952. The new Britton and Brown illustrated flora of the northeastern United States and adjacent Canada. 3 volumes. Hafner Press, New York. 1732 pp.

  • Gleason, H.A., and A. Cronquist. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. New York Botanical Garden, Bronx, New York. 910 pp.

  • Gleason, Henry A. and A. Cronquist. 1991. Manual of Vascular Plants of Northeastern United States and Adjacent Canada. The New York Botanical Garden, Bronx, New York. 910 pp.

  • Holmgren, Noel. 1998. The Illustrated Companion to Gleason and Cronquist's Manual. Illustrations of the Vascular Plants of Northeastern United States and Adjacent Canada. The New York Botanical Garden, Bronx, New York.

  • 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.

  • Mitchell, Richard S. and Gordon C. Tucker. 1997. Revised Checklist of New York State Plants. Contributions to a Flora of New York State. Checklist IV. Bulletin No. 490. New York State Museum. Albany, NY. 400 pp.

  • Muenscher, W. 1944. Aquatic plants of the United States. Cornell University Press, Ithaca, New York. 374 pp.

  • Reschke, Carol. 1990. Ecological communities of New York State. New York Natural Heritage Program, New York State Department of Environmental Conservation. Latham, NY. 96 pp. plus xi.

  • Weldy, T. and D. Werier. 2010. New York flora atlas. [S.M. Landry, K.N. Campbell, and L.D. Mabe (original application development), Florida Center for Community Design and Research http://www.fccdr.usf.edu/. University of South Florida http://www.usf.edu/]. New York Flora Association http://wwws.nyflora.org/, Albany, New York

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 http://explorer.natureserve.org were updated to be current with NatureServe's central databases as of March 2018.
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 © 2018 NatureServe, 4600 N. Fairfax Dr., 7th Floor, Arlington Virginia 22203, 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. 2018. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Available http://explorer.natureserve.org. (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:
http://www.natureserve.org/library/birdDistributionmapsmetadatav1.pdf.

Full metadata for the Mammal Range Maps of North America is available at:
http://www.natureserve.org/library/mammalsDistributionmetadatav1.pdf.

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.