Cyanea st.-johnii is a rare species of flowering plant in the bellflower family

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...

 known by the common name St. John's rollandia. It is endemic to Oahu

Oahu

Oahu or Oahu , known as "The Gathering Place", is the third largest of the Hawaiian Islands and most populous of the islands in the U.S. state of Hawaii. The state capital Honolulu is located on the southeast coast...

, where it is known only from the Koʻolau Mountains. It is a federally listed 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...

 of the United States. Like other Cyanea

Cyanea (plant)

Cyanea is a genus of lobelioid plants endemic to Hawaii. It contains more than 50 species, ranging in size from shrubs like C. eleeleensis to tall palm-like trees over 10 meters tall such as C. leptostegia...

it is known as haha 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...

.

A 2007 report estimates 70 remaining individuals divided among seven occurrences in the upper elevations of the Koʻolau Mountains. The plant grows on top of ridges, in open, windy habitat within the cloud zone. The occurrences have been separated and isolated by habitat fragmentation

Habitat fragmentation

Habitat fragmentation as the name implies, describes the emergence of discontinuities in an organism's preferred environment , causing population fragmentation...

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This 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...

 is a 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...

growing 30 to 60 centimeters tall and producing white flowers.