The Haleakala 'ahinahina, or silversword, is probably the most famous of the 28 species in the silversword alliance. Member of the silversword alliance are perhaps the most dramatic examples of adaptive radiation in the islands. These 28 species, and many subspecies, may have descended from a single ancestor, the California tarweed, which may have reached Hawaii millions of year ago.

The 'ahinahina grows between 6,500 and 10,000 feet in elevation on the upper slopes of Haleakala where it has adapted to the harsh environment. The dense covering of silver hair on its slender leaves helps to conserve moisture and protect the plant from the sun's severe rays. The 'ahinahina is low growing and has a large taproot that helps to keep it secure in high winds. Smaller, shallow, fibrous roots extend out from the taproot and allow the 'ahinahina to collect water from the surrounding loose cinder. These small roots extend as far as six feet from the plant and are easily damaged by the weight of human footsteps. This is one reason off-trail travel is strictly prohibited in Haleakala National Park.