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		Nuttall Waterweed - Elodea nuttallii
		
		
		
		
Native Species
			Global Rank: 
G5
			State Rank: 
S4
			(see State Rank Reason below)
				C-value: 
4
			
			
			
			Agency Status
			USFWS: 
			USFS: 
			BLM: 
		
			
			
				
			
			
				External Links
				
			
		 
	 
	
			
            State Rank Reason (see State Rank above)
            Elodea nuttallii is an aquatic plant that occurs in western Montana.  Populations appear to be relatively common and stable; however, half of the occurrences were found prior to 1967.  Current data on population locations, sizes, and threats are needed.
			
               
			
				- Details on Status Ranking and Review
                
					
					    
                    	
                    	    Range ExtentScoreF - 20,000-200,000 sq km (~8,000-80,000 sq mi) Area of OccupancyScoreE - 26-125 4-km2 grid cells Number of PopulationsScoreC - 21 - 80 Number of Occurrences or Percent Area with Good Viability / Ecological IntegrityScoreC - Few (4-12) occurrences with excellent or good viability or ecological integrity Environmental SpecificityScoreC - Moderate. Generalist or community with some key requirements scarce ThreatsScoreD - Low CommentNo known threats. 
                    	        
                    	     
 
 
		
	 
	
	 
		General Description
		PLANTS: Aquatic.
LEAVES: Mostly whorled in groups of 3 or 4 (Lesica et al. 2012). Leaves are recurved, linear to lanceolate, and 4–15 × 1–1.5 mm, linear (FNA 2000; Lesica et al. 2012).
INFLORESCENCE:  Male flowers occur in spathes that are somewhat spherical to ovoid, sessile, and 2.2-4.0 mm long; sepals about 2 mm long; petals minute or absent; stamens 9 (FNA 2000; Lesica et al. 2012). Female flowers occur in spathes that are linear and 9–15 mm long; sepals 1–2 mm long; petals 1–2 mm long (FNA 2000; Lesica et al. 2012). Capsules are 4–8 mm long (Lesica et al. 2012).
		
	
		Phenology
		Flowers in summer (FNA 2000).
		
	
    		Range Comments
			Throughout most of temperate North America (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).
			
		
		Observations in Montana Natural Heritage Program Database
		Number of Observations: 342
		
		
(Click on the following maps and charts to see full sized version)
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					 (Observations spanning multiple months or years are excluded from time charts)
				
			(Observations spanning multiple months or years are excluded from time charts)
		 
		
			
		
		
	
		Habitat
		Shallow to deep water of ponds, lakes, sloughs (Lesica et al. 2012), mostly calcareous (FNA 2000).  Valleys and montane (Lesica et al. 2012).
		
		
	
		Ecology
		Not considered to be weedy in North America, but is weedy in Europe (FNA 2000).
		
	
		Stewardship Responsibility
		
		
	
	References
	
		
			- Literature Cited AboveLegend:   View Online Publication View Online Publication Flora of North America Editorial Committee (FNA). 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. Flora of North America Editorial Committee (FNA). 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.
 Lesica, P., M.T. Lavin, and P.F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p. Lesica, P., M.T. Lavin, and P.F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
 
- Additional ReferencesLegend:   View Online Publication View Online Publication
 Do you know of a citation we're missing? Jeanes, E.D. 1996. Behavioral responses to water current of age-0 Arctic Grayling from the Madison River, and their use of stream habitat. M.Sc. Thesis. Bozeman, MT: Montana State University. 60p. Jeanes, E.D. 1996. Behavioral responses to water current of age-0 Arctic Grayling from the Madison River, and their use of stream habitat. M.Sc. Thesis. Bozeman, MT: Montana State University. 60p.
 Lesica, P., M.T. Lavin, and P.F. Stickney. 2022. Manual of Montana Vascular Plants, Second Edition. Fort Worth, TX: BRIT Press. viii + 779 p. Lesica, P., M.T. Lavin, and P.F. Stickney. 2022. Manual of Montana Vascular Plants, Second Edition. Fort Worth, TX: BRIT Press. viii + 779 p.
 
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