Najas filifolia - Haynes
Narrowleaf Naiad
Other English Common Names: Needleleaf Waternymph
Other Common Names: needleleaf waternymph
Taxonomic Status: Accepted
Related ITIS Name(s): Najas filifolia Haynes (TSN 503917)
Unique Identifier: ELEMENT_GLOBAL.2.133769
Element Code: PMNAJ010B0
Informal Taxonomy: Plants, Vascular - Flowering Plants - Other flowering plants
Kingdom Phylum Class Order Family Genus
Plantae Anthophyta Monocotyledoneae Najadales Najadaceae Najas
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: Najas filifolia
Taxonomic Comments: The name Najas ancistrocarpa was formerly erroneously applied to this species (Kartesz, 5/98 dataset).
Conservation Status

NatureServe Status

Global Status: G1
Global Status Last Reviewed: 09Sep2010
Global Status Last Changed: 26Nov1994
Rounded Global Status: G1 - Critically Imperiled
Reasons: Najas filifolia is a highly rare and threated aquatic plant species from the southeastern United States. It was described in the mid 1980s, but is still known from a very limited geographic range, in Georgia and Florida. This aquatic species is highly threatened by practices used to mitigate the impacts of noxious submerged vegetation, including indiscriminate consumption by the grass carp, a fish used to control aquatic vegetation, hydrologic changes and herbicide use on surrounding landscapes. The short term decline of this species is estimated at 90% in the last 50 years, and there are perhaps only a handful of populations that are believed to be extant (2-4).
Nation: United States
National Status: N1

U.S. & Canada State/Province Status
United States Florida (S1), Georgia (S1)

Other Statuses

NatureServe Global Conservation Status Factors

Range Extent Comments: Peninisular Florida and the Florida Panhandle to southwest Georgia; a Mississippi report is considered erroneous (Kartesz, 8/98 review draft dataset).

Area of Occupancy: 1-5 4-km2 grid cells
Area of Occupancy Comments: The area of occupancy for this species is estimated to be quite low given that it is currently believed to be extant at a very few locations, perhaps less than 5, and the suitable habitat available to the species is very low from habitat loss (pers. comm. D. Les, 9/8/2010).

Number of Occurrences: 1 - 5
Number of Occurrences Comments: Thirteen (eleven in Florida, two in southwest Georgia) (K. Burks pers. comm. to K. Maybury 10/4/96). In 2010, there are 9 occurrences for Florida and 3 from Georgia (two of which are from the 1940s). It is unclear why there is a reduction in the number of Florida occurrences from 1996 to 2010, except that it may be due to re-mapping the known populations (it should be noted that when a population is extirpated it is not removed from the database, but marked as 'extirpated'). Another possible explanation is that some of the populations K. Burks referred to were historic and never entered as populations into the database. One piece of supporting evidence for this supposition is the Atlas of Florida Vascular Plants cites this species in Bradford and Osceola counties, two more than Florida Natural Areas Inventory (FNAI) that include the distribution as Leon, Marion, Alachua, Lake, Highlands and Santa Rosa, counties in Florida. This species is known from Decatur, county GA. With all of this said though, field studies in 2009 to locate and assess all of the populations of this species indicated that only a very few populations are extant (pers. comm. D. Les, 9/8/2010).

Number of Occurrences with Good Viability/Integrity: None to very few (0-3)

Overall Threat Impact Comments: Threats to this species include control of noxious submerged vegetation by the introduction of grass carp, an herbivorous fish, Ctenopharyngodon idella, which eat all kinds of submerged vegetation both rare and noxious (pers. comm. K. Burks 1996, D. Les 2010). Other threats that compound the pressures on Najas filifolia, are changed to hydrologic regimes, specifically water-draw down, and use of herbicides on surrounding land (pers. comm. D. Les 9/8/2010).

Short-term Trend: Decline of >70%
Short-term Trend Comments: Najas filifolia has experienced extreme declines in the past 50 years. It is a species that is believed to have always been rare, but with threats due to management practices to control submerged noxious plants (pers. comm. D. Les 9/8/2010).

Long-term Trend: Decline of >70%
Long-term Trend Comments: The long-term trend for this species probably mimics the short-term trend, which is a precipitous decline. Even if the long trend for this species was stable-to declining prior to 50 years ago, when the extreme decline is known to have started, but given its inherent rarity, environmental specificity and sensitvity, and extreme threats, it isn't expected that the declines will suddenly or slowly retreat.

Intrinsic Vulnerability Comments: Najas filifolia is a submerged, vascular plant that is sensitive to water quality.

Environmental Specificity: Very narrow. Specialist or community with key requirements scarce.

Other NatureServe Conservation Status Information

Global Range: Peninisular Florida and the Florida Panhandle to southwest Georgia; a Mississippi report is considered erroneous (Kartesz, 8/98 review draft dataset).

U.S. States and Canadian Provinces
Color legend for Distribution Map

U.S. & Canada State/Province Distribution
United States FL, GA

Range Map
No map available.

U.S. Distribution by County Help
State County Name (FIPS Code)
FL Alachua (12001), Bradford (12007), Highlands (12055), Lake (12069), Leon (12073), Madison (12079), Marion (12083), Orange (12095), Osceola (12097), Pasco (12101), Santa Rosa (12113), Walton (12131)
GA Decatur (13087)
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
03 Upper St. Johns (03080101)+, Oklawaha (03080102)+, Kissimmee (03090101)+, Crystal-Pithlachascotee (03100207)+, withlacoochee (03110203)+, Santa Fe (03110206)+, Apalachee Bay-St. Marks (03120001)+, Lower Ochlockonee (03120003)+, Lower Flint (03130008)+, Yellow (03140103)+, Blackwater (03140104)+
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
Ecology & Life History
Basic Description: A submerged aquatic annual with highly branched stems, 7-22 cm long, and narrow leaves. This species is unique among North and Central American naiads in having recurved seeds.
Diagnostic Characteristics: No other species in this genus has curved seeds. This is the distinguishing character, and was bases for its description in 1985 (Haynes 1985).
Riverine Habitat(s): CREEK
Lacustrine Habitat(s): Shallow water
Habitat Comments: Freshwater lakes and river reaches that are darkwater habitats, i.e., the waters are tea-colored or darker due to high levels of leached organic acids.
Economic Attributes Not yet assessed
Management Summary
Stewardship Overview: Management of this species should be focused on preventing and controling non-native plants and animals from infiltrating bodies of water where this species is known to occur. Steps should be taken to eliminate herbicide use near waterbodies where this species occurs. The herbivorous fish, grass carp an indiscriminant feeder, should not be used at locations to control submerged vegetation where this species is known to occur.
Population/Occurrence Delineation Not yet assessed
Population/Occurrence Viability
U.S. Invasive Species Impact Rank (I-Rank) Not yet assessed
NatureServe Conservation Status Factors Edition Date: 09Sep2010
NatureServe Conservation Status Factors Author: Maybury, K. (1996), rev. L. Morse (1998), rev. A. Olivero (2003), L. Oliver (2010)
Management Information Edition Date: 27Sep2010
Management Information Edition Author: Oliver, L.

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).

  • Burks, K.C. 1995. Noteworthy collections: Florida. Castanea 60: 169-170.

  • Flora of North America Editorial Committee. 2000. Flora of North America north of Mexico. Vol. 22. Magnoliophyta: Alismatidae, Arecidae, Commelinidae (in part), and Zingiberidae. Oxford Univ. Press, New York. xxiii + 352 pp.

  • Haynes, R.R. 1985. A new species of Najas (Najadaceae) from the southeastern U.S.A. Brittonia 37(4): 392-393.

  • Kartesz, J. T., and C. Meacham. 1998c. Unpublished review draft of Floristic Synthesis, 17 Aug 1998. North Carolina Botanical Garden, Chapel Hill, NC.

  • 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.

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 November 2016.
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 © 2017 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. 2017. 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.