Polygonum genus -- Buckwheat family
prostrate knotweed (Polygonum aviculare) -- in July -- Well Gulch Nature Trail, Lory State Park, CO white & cream
prostrate knotweed (Polygonum aviculare) -- in August -- Deadman Road, Red Feather Lakes Area, CO
Douglas' knotweed (Polygonum douglasii) -- in July -- Satanka Cove, Lory State Park, CO green & brown