Complex sentence: This fern grows from a completely vertical crown, favoring riverbanks and sandbars, but sends out lateral stolons to form new crowns, thus forming dense colonies resistant to destruction by floodwaters.
Split into simpler sentences: This fern grows from a completely vertical crown, favoring riverbanks and sandbars, but sends out lateral stolons to form new crowns. It thus forming dense colonies resistant to destruction by floodwaters.