outlying ray flowers and 600 disk flowers and is pollinated by flying insects like Hylaeus (Nesoprosopis) volcanicus. The flower stalk can reach up to in height and has numerous tiny sticky hairs to prevent crawling insects from damaging the plant. Seeding is a critical time because damage to the flowers or stalk by insects before the seeds can mature can jeopardize the plant's entire reproductive output. History and conservation 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. Ungulates are now fenced out of the crater area and the species is legally protected from damage by humans. Gallery See also Silversword alliance References Reference links Ka’ahele Hawai’i Native Plants Federal recovery plan Hawaiian Silversword Alliance, UH Botany External links USDA Plants Profile for Argyroxiphium sandwicense subsp. macrocephalum (Hawai'i silversword) USGS: Haleakalā Silversword (Argyroxiphium sandwicense subsp. macrocephalum) sandwicense subsp. macrocephalum Endemic flora of Hawaii Biota of Maui Haleakalā National Park Plant subspecies