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Eurasian Watermilfoil (Myriophyllum spicatum)

Status:

Listed Noxious Weed In Montana

History:

First Montana Specimen Collected 1

    

County:

None

Year:

None
"Eurasian Watermilfoil may have been introduced to the north American continent a Chesapeake bay in the 1880's. Although Couch and Nelson present evidence that the first collection of Eurasian Watermilfoil was made from a pond in the District of Columbia during the fall of 1942. By 1985 Eurasian Watermilfoil had been found in 33 states and the District of Columbia." (Simmons)    
   
   
   
   
   
   
   
   
   
   
   

Habitat:

 

 

 

Growth Habit:

 

Submersed Perennial Plant.

 

Leaves:

 

Finely dissected, feather like, whorls of 4 (rarely 5) around the stem.

 

Stem:

 

Tassel like tips, often red.

 

Flower:

 

Tiny pinkish on reddish spikes.

 

Roots:

 

 

 

Seeds:

 

Seeds produced but seedlings rare.

 

Other Notes:

 

Currently no known infestations in the Yellowstone River Corridor.

“Eurasian Watermilfoil can develop into a land form.&nbsp; Leaves of the land form are
smaller, stiffer and have fewer divisions.&nbsp; If these plants are submerged,
new growth with aquatic leaves develops in 7-10 days, but the first leaves
formed have relatively few divisions and only later do the divisions
increase to 12 or more leaflet pairs.

Eurasian Watermilfoil forms dense canopies that often shade out native vegetation.&nbsp;
A poor habitat for waterfowl, fish and other wildlife.” (Simmons, 30)