I found this tiny plant growing next to the dock at my family's lake cabin over Labor Day weekend. It was growing in an area that is frequently underwater.
Another picture with a dime for scale.
A few more were growing on the other side of the dock.
I have very tentatively identified it as water star-grass Heteranthera dubia a typically aquatic plant, but if any plant folks out there think otherwise I'd be happy to hear your thoughts. The book I was looking it up in, Wetland Plants of Minnesota, describes it as "sometimes exposed and forming small leafy rosettes". Interestingly it also says it is sometimes used as an aquarium plant.
I always find it fascinating how many wetland plants can take very different forms depending on whether they are growing submerged or more terrestrially.