You may have wondered why when you pull a weed in your front lawn, it always comes back. The roots of grass bind into the soil very well. When we pull out a grass plant, we are only taking out a small part of the entire root system. In some species of grass, the roots can reach as far down into the soil as six feet. The flowering parts of the plant are called inflorescences.
Racemes are flowers that are on short stocks, extending from the stem.
Panicles are flowers with their own stalks. Although grasses seem like very simple structural plants, they are actually pretty complex organisms. Hypothesis - Grasses will vary in abundance and type the further away they grow from the water. You may be walking in the mud. The sites should vary in exposure to sun, type of soil, and current of the water.