Brighamia insignis, commonly known as Ōlulu or Alula in 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...

, or colloquially as cabbage on a stick, is a critically endangered species of Hawaiian lobelioid

Hawaiian lobelioids

The Hawaiian lobelioids are a group of flowering plants in the bellflower family, Campanulaceae, all of which are endemic to the Hawaiian Islands. This is the largest plant radiation in the Hawaiian Islands, and indeed the largest on any island archipelago, with over 125 species...

 in the bellflower

Campanula

Campanula is one of several genera in the family Campanulaceae with the common name bellflower. It takes its name from their bell-shaped flowers—campanula is Latin for "little bell"....

 family, Campanulaceae

Campanulaceae

The family Campanulaceae , of the order Asterales, contains about 2000 species in 70 genera of herbaceous plants, shrubs, and rarely small trees, often with milky non-toxic sap...

. It is native to the islands 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",...

 and Niihau

Niihau

Niihau or Niihau is the seventh largest of the inhabited Hawaiian Islands in the U.S. state of Hawaii, having an area of . Niihau lies southwest of Kauai across the Kaulakahi Channel. Several intermittent playa lakes provide wetland habitats for the Hawaiian Coot, the Black-winged Stilt, and the...

. This short-lived perennial species is a member of a unique endemic 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...

an genus with only one other species. It is now extremely rare. In 1994 the United States Fish and Wildlife Service

United States Fish and Wildlife Service

The United States Fish and Wildlife Service is a federal government agency within the United States Department of the Interior dedicated to the management of fish, wildlife, and natural habitats...

 reported five populations totaling 45 to 65 individuals, and listed the plant as an endangered species

Endangered species

An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...

.

B. insignis is a potentially branched plant with a succulent stem

Plant stem

A stem is one of two main structural axes of a vascular plant. The stem is normally divided into nodes and internodes, the nodes hold buds which grow into one or more leaves, inflorescence , conifer cones, roots, other stems etc. The internodes distance one node from another...

 that is bulbous at the bottom and tapers toward the top, ending in a compact 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:...

 of fleshy 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....

. The stem is usually 1–2 m (3.3–6.6 ft) in height, but can reach 5 m (16.4 ft). The plant blooms in September through November. It has clusters of fragrant yellow 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 in groups of three to eight in the leaf axils. The scent has been compared to honeysuckle

Honeysuckle

Honeysuckles are arching shrubs or twining vines in the family Caprifoliaceae, native to the Northern Hemisphere. There are about 180 species of honeysuckle, 100 of which occur in China; Europe, India and North America have only about 20 native species each...

. Petal

Petal

Petals are modified leaves that surround the reproductive parts of flowers. They often are brightly colored or unusually shaped to attract pollinators. Together, all of the petals of a flower are called a corolla. Petals are usually accompanied by another set of special leaves called sepals lying...

s are fused into a tube 7 centimetre long. The fruit

Fruit

In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...

 is a capsule

Capsule (fruit)

In botany a capsule is a type of simple, dry fruit produced by many species of flowering plants. A capsule is a structure composed of two or more carpels that in most cases is dehiscent, i.e. at maturity, it splits apart to release the seeds within. A few capsules are indehiscent, for example...

 13 to 19 mm (0.511811023622047 to 0.748031496062992 in) long containing numerous seed

Seed

A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...

s.

B. insignis is found at elevations from sea level to 480 m (1,574.8 ft) in mesic shrublands and dry forests

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...

 that receive less than 170 cm (66.9 in) of annual rainfall. It grows on rocky ledges with little soil

Soil

Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...

 and steep sea cliff

Cliff

In geography and geology, a cliff is a significant vertical, or near vertical, rock exposure. Cliffs are formed as erosion landforms due to the processes of erosion and weathering that produce them. Cliffs are common on coasts, in mountainous areas, escarpments and along rivers. Cliffs are usually...

s. Associated plants include āhinahina (Artemisia spp.) akoko (Euphorbia celastroides

Euphorbia celastroides

Euphorbia celastroides, sometimes also known as Chamaesyce celastroides, is a species of spurge closely related to the poinsettia. This species develops into a round-shape shrub. This species is endemic to the Hawaiian Islands. E...

), alahee (Psydrax odorata

Psydrax odorata

Psydrax odorata, known as Alahee in Hawaiian, is a species of flowering shrub or small tree in the coffee family, Rubiaceae, that is native to the Pacific Islands, Malesia and Australasia...

), kāwelu (Eragrostis variabilis), pili (Heteropogon contortus

Heteropogon contortus

Heteropogon contortus is a tropical, perennial tussock grass with a native distribution encompassing Southern Africa, southern Asia, Northern Australia and Oceania. The species has also become a naturalised weed in tropical and subtropical regions in the Americas and East Asia. The plant grows to ...

), kokio ula (Hibiscus kokio

Hawaiian hibiscus

Hawaiian hibiscus are the seven known species of hibiscus regarded as native to Hawaii. Although tourists regularly associate the hibiscus flower with their experiences visiting the US state of Hawaii, and the plant family Malvaceae includes a relatively large number of species that are native to...

), ānaunau (Lepidium

Lepidium

Lepidium is a genus of plants in the mustard family Brassicaceae. It includes about 175 species found worldwide, including cress and pepperweed; additional common names include peppercress, peppergrass, and pepperwort...

 serra), nehe (Lipochaeta succulenta

Lipochaeta succulenta

Lipochaeta succulenta is a plant endemic to all the main Hawaiian islands except Lanai.L. succulenta is a perennial, clump-forming subshrub up to tall with lax, spreading stems that root at the nodes. Leaves are glossy green, succulent, and long...

), pokulakalaka (Munroidendron racemosum

Munroidendron racemosum

Munroidendron racemosum , the sole species in the genus Munroidendron, is an extremely rare flowering plant in the ivy family, Araliaceae, that is endemic to the island of Kauai in Hawaii.-Description:...

), and ilima (Sida fallax

Sida fallax

Sida fallax, known as ilima in Hawaiian, is a species of herbaceous flowering plant in the Hibiscus family, Malvaceae, that occurs on most of the Pacific Islands. The flowers are small, in diameter, have five petals, and are a golden yellow in color. Plants may be erect or prostrate and are found...

).

According to the U.S. Botanical Gardens, its only pollinator

Pollinator

A pollinator is the biotic agent that moves pollen from the male anthers of a flower to the female stigma of a flower to accomplish fertilization or syngamy of the female gamete in the ovule of the flower by the male gamete from the pollen grain...

 was a certain type of now-extinct hawk moth

Sphingidae

Sphingidae is a family of moths , commonly known as hawk moths, sphinx moths and hornworms, that includes about 1,200 species . It is best represented in the tropics but there are species in every region . They are moderate to large in size and are distinguished among moths for their rapid,...

. This has made it all but impossible for B. insignis to reproduce on its own. Therefore, individuals only produce seed when artificially pollinated by humans.

Other threats to the species have included exotic plant species

Introduced species

An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...

, feral goat

Feral goat

The feral goat is the domestic goat when it has become established in the wild. Feral goats occur in Australia, New Zealand, Ireland, Great Britain, Hawaii, the Galapagos and in many other parts of the world...

s and pigs, slug

Slug

Slug is a common name that is normally applied to any gastropod mollusc that lacks a shell, has a very reduced shell, or has a small internal shell...

s, rat

Rat

Rats are various medium-sized, long-tailed rodents of the superfamily Muroidea. "True rats" are members of the genus Rattus, the most important of which to humans are the black rat, Rattus rattus, and the brown rat, Rattus norvegicus...

s, fire

Fire

Fire is the rapid oxidation of a material in the chemical process of combustion, releasing heat, light, and various reaction products. Slower oxidative processes like rusting or digestion are not included by this definition....

, and infestations of carmine spider mites (Tetranychus cinnabarinus). There is also a hiking trail

Hiking

Hiking is an outdoor activity which consists of walking in natural environments, often in mountainous or other scenic terrain. People often hike on hiking trails. It is such a popular activity that there are numerous hiking organizations worldwide. The health benefits of different types of hiking...

 near one of the populations. The plant grows on steep, exposed cliffs and has been damaged by hurricanes and landslide

Landslide

A landslide or landslip is a geological phenomenon which includes a wide range of ground movement, such as rockfalls, deep failure of slopes and shallow debris flows, which can occur in offshore, coastal and onshore environments...

s.

Despite its rarity in the wild it is not hard to cultivate in a nursery, and it has come into use as a novel ornamental plant

Ornamental plant

Ornamental plants are plants that are grown for decorative purposes in gardens and landscape design projects, as house plants, for cut flowers and specimen display...

.