Freshwater swamps are commonly found inland, while saltwater swamps are usually found along coastal areas. Freshwater swamps form around lakes and streams. Rain and seasonal flooding cause water levels to fluctuate. In the wet soil, water-tolerant vegetation grows and helps maintain a moist, swampy condition. The prostrate system is attached to some substratum, grows apically and gives rise to numerous photosynthetic and rhizoidal filaments. Rhizoidal filaments sometimes penetrate the substratum. The erect system develops from the prostrate system and is composed of one or more and usually branched photosynthetic filaments. Hence Rhizopodium is able to survive in swampy areas.