Despite their very different appearances, the silverswords are very closely related to the genus "Dubautia". Although some "Dubautia" are radically different from silverswords, those found in wet forests and alpine deserts clearly grade into the form of silverswords. Hybrids between "Argyroxiphium sandwicense" and "Dubautia menziesii" are common in Haleakalā Crater. Although the two species are quite distinct, the hybrids span the entire range of variation between them. Silverswords and greenswords are highly sensitive to disturbance. The best-known species, "A. sandwicense," has dwindled to 50 plants existing in the wild, due in large part to disturbance by grazing animals introduced to their natural habitat over the past hundred years . Their shallow root systems are easily crushed in the boggy soil or loose volcanic cinders they grow in. The succulent leaves are eaten by goats in the dry summits, and pigs frequently disturb the fragile bog vegetation. All species are highly restricted in range, and even those that are protected are vulnerable to catastrophic events. The East Maui greensword ("A. virescens") is apparently extinct, but in 1989 plants were discovered that appear to be hybrids between it and the Haleakalā Silversword. The Mauna Kea and Mauna Loa silverswords both have small populations, but are being cultivated and outplanted in protected areas. The largest population of Mauna Loa silverswords is in Kahuku, which was recently acquired by Hawaii Volcanoes National Park. Botanist L. Walker created a system of ideal conditions in which to outsource the growing and planting of certain "Argyroxiphium", which would assist in efforts to bring the species back to the wilderness in strength .   now in "Wilkesia"