Haleakala Silversword - Maui, HI
Posted by: silverquill
N 20° 42.606 W 156° 15.181
4Q E 786121 N 2292491
Quick Description: Found nowhere else in the world other than here at the higher elevations of Mt. Haleakala on the island of Maui, Hawaii, the silversword has been an endangered species since 1922. Here at this garden they are grown and protected.
Location: Hawaii, United States
Date Posted: 2/25/2009 5:52:00 PM
Waymark Code: WM5XKF
From the Wikipedia:
The Haleakala silversword (Argyroxiphium sandwicense macrocephalum) is part of the family Asteraceae. The silversword in general is referred to as ?ahinahina in Hawaiian (literally, "very gray"), and it has been a threatened species according to the U.S. Fish & Wildlife service since May 15, 1922. Excessive grazing by cattle and goats and vandalism inflicted by people in the 1920s caused near extinction of the Haleakala silversword. The plant has been strictly monitored and protected by the government since and is considered a successful conservation story, although threat to the species remain. This plant is only found on the island of Maui in Haleakala National Park at an elevation of 2,100 to 3,000 m on the Haleakala summit depression, the rim summits, and surrounding slopes of the dormant Haleakala volcano.
Silversword plants in general grow on volcanic cinder, a dry, rocky substrate that is subject to freezing temperatures and high winds. Haleakala silversword has numerous sword-like succulent leaves covered with silver hairs. 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 dominate for the majority of the plant's life which may be greater than fifty 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 to adapt to the extreme temperatures by focusing the sunlight to converge at this point and warm the plant.
At senescence which often occurs when the plant reaches a diameter of approximately one-half meter, the plant produces a tall stalk of maroon ray flowers which resemble the sunflower in just a few weeks. Flowering usually occurs in June or July. This flowering stalk may have up to 600 heads of up to 40 outlying ray flowers and 600 disk flowers and is pollinated by flying insects like Hylaeus (Nesoprosopis) volcanicus. The flower stalk can reach up to two meters in height and has numerous tiny sticky hairs to prevent crawling insects from damaging the plant. 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 monocarpic plant goes to seed and dies.