Invasive SpeciesHydrilla

Hydrilla verticillata
NOT FOUND by vitalsleuth
ID Confirmed
Quality checked by manyeyes
Peer reviewed by
Field Notes
I'm always on the lookout for plants floating by as we're swimming and playing in the water. The water was calm this weekend, so there weren't as many detached plants making their way to our shore as I had hoped. This one caught my eye as a hydrilla look-alike, but I'm quite convinced it's a native waterweed (Elodea canadensis or Elodea nutallii).
Supporting Evidence
Photo of my evidence.
This photo shows that this is NOT hydrilla because it has whorls of three leaves. Hydrilla has 4 or more leaves per whorl.
Species Observation: Species Looked For
Did you find it?: 
I think I did not find it
Scientific name:
Hydrilla verticillata
Common name:
Sampling method: 
Just looking around
Photo of our sampling method.
Place Studied
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Map this species
N 44.473694 °
W -69.510518 °
Observation Site Information
A photo of our study site.
Freshwater - In a pond or lake
Trip Information
China Lake
Trip date: 
Fri, 2012-08-17 10:00
Town or city: 
Type of investigation: 
Species Survey
Lower Kennebec
MIDAS Code: 


Thanks for your ID guess (I like knowing more about the natives I'm finding!), and for the tip about looking for visible teeth on the leaf margins of hydrilla. The books say that the native waterweeds have serrated edges, too, but it sounds like I'd need a hand lens to see them.

I feel much smarter this morning!

You mentioned the number of leaves per whorl as a distinguishing characteristic. You'd also see -- with naked eye -- teeth on the leaf margins of hydrilla. I think this is Elodea canadensis based on the relatively wide leaves (compared to E nutallii) and the bunching of whorls at the stem tip. It's always good to take a careful look at Elodea plants. Thanks for being on the lookout.