Crinum americanum

This species is found in many localities in the southeastern United States.  It is aquatic or semi-aquatic, being found in areas that are flooded for at least part of the year. 

Many similar plants are found throughout the the Americas, into South America.   These southern forms are called C. erubescens or sometimes C. americanum var. erubescens, or they may have even been called by other names. 

In this huge geographic region (North, Central, and South America) many variants are known which have been given names (robustum, giga, etc.).  Apparently all forms make stolons.  Some require aquatic conditions to bloom, and others seem happy to bloom in a regular flowerbed (e.g., C. erubescens). 

The green scape that is typical of C. americanum can be seen in this photo.