Some type of escapee
These plants were in a heavily shaded area in the first cut of woods, about 30 yards off a highway. They were in a dense patch about 4 feet across, and were not likely planted at that location. The leaves were 12-14 inches tall, about 0.3 inch wide, single-veined, smooth, had rounded tips and were heavily keeled underneath. The bulbs averaged a bit more than 1 inch across. The two photos were taken this afternoon.