Wilkesia gymnoxiphium (Hawaiian

Hawaiian language

The Hawaiian language is a Polynesian language that takes its name from Hawaii, the largest island in the tropical North Pacific archipelago where it developed. Hawaiian, along with English, is an official language of the state of Hawaii...

 iliau), is a species of flowering plant

Flowering plant

The flowering plants , also known as Angiospermae or Magnoliophyta, are the most diverse group of land plants. Angiosperms are seed-producing plants like the gymnosperms and can be distinguished from the gymnosperms by a series of synapomorphies...

 in the sunflower

Sunflower

Sunflower is an annual plant native to the Americas. It possesses a large inflorescence . The sunflower got its name from its huge, fiery blooms, whose shape and image is often used to depict the sun. The sunflower has a rough, hairy stem, broad, coarsely toothed, rough leaves and circular heads...

 family, Asteraceae

Asteraceae

The Asteraceae or Compositae , is an exceedingly large and widespread family of vascular plants. The group has more than 22,750 currently accepted species, spread across 1620 genera and 12 subfamilies...

, that is endemic to the island of Kauai

Kauai

Kauai or Kauai, known as Tauai in the ancient Kaua'i dialect, is geologically the oldest of the main Hawaiian Islands. With an area of , it is the fourth largest of the main islands in the Hawaiian archipelago, and the 21st largest island in the United States. Known also as the "Garden Isle",...

 in Hawaii

Hawaii

Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...

. Wilkesia is one of three genera, with Argyroxiphium

Argyroxiphium

Argyroxiphium is a small genus of five species in the sunflower family, Asteraceae. Its members are known by the common name of silversword or greensword due to their long, narrow leaves and the silvery hairs on some species. It belongs to a larger radiation of over 50 species, including the...

(silverswords and greenswords) and Dubautia

Dubautia

Dubautia is a genus of flowering plant in the sunflower family, Asteraceae, that is endemic to Hawaii. It contains more species than the other two genera in the silversword alliance, including cushion plants, shrubs, trees, and lianas.-Selected species:...

(a larger group with many varied species) that are believed to be descendant from a single species related to the North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

n tarweed. The members of these three genera constitute what is called the silversword alliance

Silversword alliance

Silversword alliance refers to an adaptive radiation of over 50 species in the composite or sunflower family, Asteraceae. The group is endemic to Hawaii, and is derived from a single immigrant to the islands...

, a group whose exceedingly close genetic heritage is not reflected in their exceptionally diverse morphologies.

Description

W. gymnoxiphium is a monocarpic

Monocarpic

Monocarpic plants are those that flower, set seeds and then die. Other terms with the same meaning are hapaxanth and semelparous. The term was first used by Alphonse de Candolle....

 rosette

Rosette (botany)

In botany, a rosette is a circular arrangement of leaves, with all the leaves at a single height.Though rosettes usually sit near the soil, their structure is an example of a modified stem.-Function:...

 shrub

Shrub

A shrub or bush is distinguished from a tree by its multiple stems and shorter height, usually under 5–6 m tall. A large number of plants may become either shrubs or trees, depending on the growing conditions they experience...

, with rosettes elevated on woody stems as much as 5 m (16.4 ft) tall. Distinctive features include a usually unbranched, monocarpic axis, leaves

Leaf

A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....

 in whorls of 9-15 that join to form a basal sheath around the stem, and peduncles

Peduncle (botany)

In botany, a peduncle is a stem supporting an inflorescence, or after fecundation, an infructescence.The peduncle is a stem, usually green and without leaves, though sometimes colored or supporting small leaves...

 that are commonly branched. Fountains of yellow, daisy

Bellis perennis

Bellis perennis is a common European species of Daisy, often considered the archetypal species of that name. Many related plants also share the name "Daisy", so to distinguish this species from other daisies it is sometimes qualified as Common Daisy, Lawn Daisy or occasionally English daisy. It is...

-like flower

Flower

A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...

s form mostly May to July. When unbranched the plant dies after flowering, but if it branches into multiple heads (as may happen if the top is broken off), each head will flower and die separately.

Habitat

This species occurs only on Kauai

Kauai

Kauai or Kauai, known as Tauai in the ancient Kaua'i dialect, is geologically the oldest of the main Hawaiian Islands. With an area of , it is the fourth largest of the main islands in the Hawaiian archipelago, and the 21st largest island in the United States. Known also as the "Garden Isle",...

, on dry ridges or dry

Hawaiian tropical dry forests

The Hawaiian tropical dry forests are a tropical dry broadleaf forest ecoregion in the Hawaiian Islands. They cover an area of on the leeward side of the main islands and the summits of Niihau and Kahoolawe. These forests are either seasonal or sclerophyllous. Annual rainfall is less than and...

 to mesic forest

Forest

A forest, also referred to as a wood or the woods, is an area with a high density of trees. As with cities, depending where you are in the world, what is considered a forest may vary significantly in size and have various classification according to how and what of the forest is composed...

s. The most common location is along the slopes of Waimea Canyon

Waimea Canyon State Park

Waimea Canyon, also known as the Grand Canyon of the Pacific, is a large canyon, approximately ten miles long and up to 3,000 feet deep, located on the western side of Kauai in the Hawaiian Islands. Waimea is Hawaiian for "reddish water," a reference to the erosion of the canyon's red soil...

. It grows at elevations of 425–1100 m (1,394.4–3,608.9 ft) in areas that receive 800–2000 mm (31.5–78.7 in) of annual precipitation.

Heavily grazed by feral

Feral

A feral organism is one that has changed from being domesticated to being wild or untamed. In the case of plants it is a movement from cultivated to uncultivated or controlled to volunteer. The introduction of feral animals or plants to their non-native regions, like any introduced species, may...

 goat

Goat

The domestic goat is a subspecies of goat domesticated from the wild goat of southwest Asia and Eastern Europe. The goat is a member of the Bovidae family and is closely related to the sheep as both are in the goat-antelope subfamily Caprinae. There are over three hundred distinct breeds of...

s in the canyon, they are most often seen on inaccessible slopes. However, a dense population can be seen in a fenced enclosure just off the road heading to Kōkee State Park

Koke'e State Park

Kōkee State Park is located in northwestern Kauai in the Hawaiian Islands. It includes a museum at the marker on State Road 550, which focuses on the weather, vegetation, and bird life; a lodge which serves food and sells gifts; cabins for rent; and hiking trails...

.