Scientific Name
Argyroxiphium kauense (Rock & Neal) O.Deg. & I.Deg.
Synonym(s)
Argyroxiphium sandwicense var. kauense
Common Name(s)
Ka'u Silversword, Mauna Loa Silversword
Scientific Classification
Family: Asteraceae
Subfamily: Asteroideae
Tribe: Madieae
Genus: Argyroxiphium
Etymology
The specific epithet "kauense" (pronounced "kau-EN-see") means "Of or from Ka'ū". It refers to the origin of this species, Ka'ū🡕, the southernmost and largest district of Hawaiʻi County, Hawaii, located on the island of Hawaiʻi.
Origin
Argyroxiphium kauense is native to Hawaii. It occurs in montane shrubland, bogs, and open mesic forest on the eastern and southern slopes of Mauna Loa in the Ka'ū District on the island of Hawaiʻi.
Description
Argyroxiphium kauense is an erect rosette shrub with dagger-shaped leaves covered with fine, short silvery hairs. It can grow up to 4.25 feet (1.3 m) tall and up to 32 inches (80 cm) in diameter, usually single-stemmed or occasionally with a few branches. The leaves are triangular in cross-section, measuring up to 16 inches (40 cm) long and 0.3 inches (0.7 cm) wide.
In summer, a flowering stalk emerges from the center of the rosette and can grow up to 6.6 feet (2 m) tall, bearing 100 to 300 flower heads, each with 50 to 200 small, densely clustered flowers. The flowers are pale yellow, yellow with a rose tinge, rose, or sometimes wine-red. The fruits are dry, black, single-seeded achenes that can reach up to 0.4 inches (1 cm) in length. This plant is monocarpic, meaning it blooms only once in its life, sets fruit, and then dies.
How to Grow and Care for Argyroxiphium kauense
Hardiness: USDA hardiness zone 10a to 10b: from 30°F (-1.1°C) to 40°F (4.4°C).
The Silversword alliance comprises about 50 plant species belonging to three genera, all endemic to the Hawaiian Islands. They get their common name from the visually impressive Silversword.
Argyroxiphium kauense is endemic to the eastern and southern slopes of Mauna Loa on the island of Hawaiʻi. It occurs in a much broader range of habitats than the closely related and better-known Haleakalā silversword (Argyroxiphium sandwicense subsp. macrocephalum). It is found in montane shrubland, bogs, and open mesic forest.
Although threatened by damage from feral pigs, goats, and mouflon sheep, most areas where it currently exists are now protected, and the National Park Service and the Hawai'i State Department of Forestry and Wildlife actively manage the species. It is a federally listed endangered species of the United States. Three known occurrences are remaining, for a total of fewer than 1000 individuals.
Links
- Back to genus Argyroxiphium
- Succupedia: Browse succulents by Scientific Name, Common Name, Genus, Family, USDA Hardiness Zone, Origin, or cacti by Genus
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