Though it looks like a small palm, it's more closely related to the lilies. I found these bodacious bloomers at the refuge last week. The plants die after flowering and fruiting, but produce lateral buds that start new plants around the original.
The flowers of many yucca varieties are edible. They can be eaten raw or cooked. Fire up Google and you'll find some amazing recipes. However, you should NEVER eat wild plants unless you REALLY know EXACTLY what you've harvested and EXACTLY how safe - or otherwise - it is!