Last week on my visit to Brooklake I noticed this aquatic plant floating on the water. Not knowing what it was and thinking it might be a unwanted invasive; I contacted Chris Carrel ( Friends of the Hylebos) and Jason Gerwen ( FW Parks ) to see if they could answer my question.
I also did some internet checking on invasive plants and found a very informative King County site on Noxious Weeds . The plant in question was not on the list of noxious weeds. Doing more clicking I found photos of the plant Common Duckweed - Lemna minor, on a Texas Fish and Wildlife page and sent the information to my consultants Chris and Jason. Our group consensus is, the plant is indeed Common Duckweed.
Jason, also consulted with Dan Smith the City's water quality coordinator, who reported that the plant is not a problem we need to be concerned about at this time. Due to the warm temperatures this summer, we are seeing higher quantities of it this year.
Although in some areas of the country this plant can become a problem, once the fall stream flow picks up I think the Duckweed will not thrive.
One small mystery solved.