Also known in Hawaiian as the 'ahinahina. They only grow at the top of the volcano at the 10,000 foot level.
Because of that they were on their way to extinction from tourists unintentionally destroying them by walking near them or trying to dig them up to take home. The plants have a very shallow root system so stepping on a rock next to them can crush the roots and kill the plant. They are now a protected plant and carry a hefty fine for messing with them.
The silversword can live up to 90 years and only blooms once in it's life. The stalk that carries the blooms grows out of the center of the plant and can get over six feet tall with more than 600 blooms on a single stalk. Once the silversword blooms it dies so the seeds from the blooms can dry and be spread by the wind to grow new plants.