Invasive SpeciesCurly leaf pondweed

Potamogeton crispus
NOT FOUND by jnye
ID Confirmed
Quality checked by E. Gribben
Peer reviewed by
Field Notes
Our prediction: Based on our background research we predict that we will NOT find curly pond weed invading Johnson Pond. We are happy to be outside on a beautiful day for Vital Signs training! Sitting by the side of a Johnson Pond, feeling a gentle breeze and enjoying the 72ºF temperature! We hear bumble bees and traffic. We see willow trees, movement in the water as the wind ripples through. We see cat tails by the pond's edge that have burst and are fluffy. Questions and problems: We wish our camera had a macro setting and a backlight compensation control. We had a hard time getting a photo of the leaf against the light. Chronically underexposed. Also we were lacking a stem on our plant which would have made our identification more definite. We also had a hang up on what would have been a beautiful weed weasel cast as the rope snagged in the surrounding plant life. This gave us a smaller sample of plant life than we might have otherwise had.
Supporting Evidence
Photo of my evidence.
Curly pondweed leaves are between 4 and 10 cm long and 1cm or less in width. As you can see from our photo, this leaf fits within the length parameters, but appears to be a little too chubby for the width requirement.
Photo of my evidence.
Here we examined the leaf edges. Curly pondweed has edges that are both serrated and ruffled. Our specimen shows serrations, but no ruffles....
Photo of my evidence.
Color comparison. As you can see in the photo, our specimen is brown in color and considerably darker than the species ID card indicates curly pondweed should be.
Species Observation: Species Looked For
Did you find it?: 
I think I did not find it
Scientific name:
Potamogeton crispus
Common name:
Curly leaf pondweed
Sampling method: 
Weed weasel
Photo of our sampling method.
Place Studied
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Map this species
N 44.564810 °
W -69.665040 °
Observation Site Information
A photo of our study site.
Freshwater - In a pond or lake
Trip Information
Johnson Pond
Trip date: 
Fri, 2017-07-28 11:30
Town or city: 
Type of investigation: 
Species Survey
Lower Kennebec
MIDAS Code: 


Greetings jnye,

My apologies for the delay in reviewing your Vital Signs submission. I have been out hunting for aquatic invaders on the lakes of Maine!

You are quite right in your findings: the plant you found is NOT curly leaf pondweed, for all of the reasons you explain and more. I believe what you found are native willow leaves. Maine is home to numerous willow species that live at the water's edge.

For future reference, here is a tip on backlighting your subject. Take the wet leaf and stick it to a pane of glass (a schoolroom or car window will do nicely, but if you are away from civilization you can use a smooth clear jar) then take the picture. Go for clear focus, even though you do not have a macro lens, as you can crop and zoom later to enlarge the image. You may have to fiddle with the light, color, and crop controls after the fact to produce the clearest, most revealing image, but the average smart phone is capable of yielding excellent results.

I enjoyed reading your observations from your visit to Johnson Pond. Please keep up the great work, keeping a watchful eye out for aquatic invaders.

All the best,

Roberta Hill
Invasive Species Program Director
Maine Volunteer Lake Monitoring Program