water plants in the river - pondweed - potamogeton natans

pondweed potamogeton background natural plant flora nature leaves water potamogetonaceae freshwater lake surface summer floating fresh flower river green submersed quiet season environment natans floatingleaf european broadleaved serbian aquatic color grow hygroamblystegium varium nobody strictifolius spread stoneworts spring leaf white growth bloom springtime botanical inflorescence outdoor close plants