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Back on the summit of Haleakala ...
One would tend not to think of this chilly and inhospitable environment as home to much of anything, but there are a few rare plants and animals that exist only here. Before I tell you what this is, I have to mention that here on the summit there are several signs posted warning you to walk only on marked trails, because, even only one step outside, you could be walking on microbes that live only here and would be crushed to death. I found that to be particularly surprising.
This rare plant, the Haleakala Silversword, or ʻāhinahina in Hawaiian, grows only at an elevation of 6,900 to 9,800 ft on the dormant Haleakalā volcano. The Haleakalā silversword has been a threatened species as defined by the U.S. Fish and Wildlife Service, since May 15, 1992. Prior to that time, excessive grazing by cattle and goats, and vandalism inflicted by people in the 1920s, had caused its near extinction. Before the National Park Service was granted control of Haleakalā volcano, visitors to the volcano's summit often participated in the common practice of uprooting a silversword plant and then rolling it on the jagged lava rock terrain, drying the flowers for arrangements, or using the plant as kindling. Because the delicate, shallow root structure can be crushed by walking in the rocks around the plant, they are very sensitive to foreign elements. Feeding by goats also severely damaged many plants and prevented reproduction. It has since recovered somewhat, but remains threatened.
From Wikipedia: "The Haleakalā silversword has numerous sword-like succulent leaves covered with silver hairs. Silversword plants in general grow on volcanic cinder, a dry, rocky substrate that is subject to freezing temperatures and high winds. The skin and hairs are strong enough to resist the wind and freezing temperature of this altitude and protect the plant from dehydration and the sun.
The plant's base of leaves, arranged in a spherical formation at ground level of the plant, dominates for the majority of the plant's life—which may be greater than 50 years. The leaves are arranged so that they and the hairs of the leaves can raise the temperature of the shoot-tip leaves up to 20 °C (68 °F), thereby having adapted to the extreme high-altitude temperatures by focusing the sunlight to converge at this point and warm the plant.
Silversword is known as a monocarpric plant, meaning it produces seeds only once before its death. Seeding of the plant is very sensitive because damage to the flowers or stalk by insects before reseeding further hinders the threatened species’ propagation. The leaves become limp and dry as the plant goes to seed and dies before being able to fully propagate itself.
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