Phreatia listeri is a species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of epiphytic

Epiphyte

An epiphyte is a plant that grows upon another plant non-parasitically or sometimes upon some other object , derives its moisture and nutrients from the air and rain and sometimes from debris accumulating around it, and is found in the temperate zone and in the...

 orchid. It is endemic to Christmas Island

Christmas Island

The Territory of Christmas Island is a territory of Australia in the Indian Ocean. It is located northwest of the Western Australian city of Perth, south of the Indonesian capital, Jakarta, and ENE of the Cocos Islands....

, an Australia

Australia

Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

n territory in the north-eastern Indian Ocean

Indian Ocean

The Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded on the north by the Indian Subcontinent and Arabian Peninsula ; on the west by eastern Africa; on the east by Indochina, the Sunda Islands, and...

. Its specific epithet honours British zoologist and plant collector

Plant collecting

Plant collecting involves procuring live or dried plant specimens, for the purposes of research, cultivation or as a hobby.-Collection of live specimens:...

 Joseph Jackson Lister

Joseph Jackson Lister (naturalist)

Joseph Jackson Lister FRS was a British zoologist and plant collector from Leytonstone who collected biological specimens during travels in Africa, Asia, Australasia and the Pacific region....

, who visited the island on HMS

Her Majesty's Ship

Her or His Majesty's Ship is the ship prefix used for ships of the navy in some monarchies, either formally or informally.-HMS:* In the British Royal Navy, it refers to the king or queen of the United Kingdom as appropriate at the time...

 Egeria in 1887.

Description

Phreatia listeri is a small, clump-forming epiphytic orchid. The long, thin 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....

 are 40–110 mm long and 2–5 mm wide. The 40–80 mm long inflorescence

Inflorescence

An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...

 has many tiny, greenish-white 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, only about 1 mm across. The orchid's lip is concave and contracted at the base. The seed 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...

 is 25 mm long.

Distribution and habitat

Found only on Christmas Island, the orchid is common on rainforest

Rainforest

Rainforests are forests characterized by high rainfall, with definitions based on a minimum normal annual rainfall of 1750-2000 mm...

 trees growing on the plateau and the upper terraces

Marine terrace

A marine terrace, coastal terrace, raised beach or perched coastline is a relatively flat, horizontal or gently inclined surface of marine origin, mostly an old abrasion platform which has been lifted out of the sphere of wave activity . Thus it lies above or under the current sea level, depending...

 of the island.

Relationships

The orchid resembles both P. limenophylax Benth. from Norfolk Island

Norfolk Island

Norfolk Island is a small island in the Pacific Ocean located between Australia, New Zealand and New Caledonia. The island is part of the Commonwealth of Australia, but it enjoys a large degree of self-governance...

, and P. minutiflora Lindl. from Borneo

Borneo

Borneo is the third largest island in the world and is located north of Java Island, Indonesia, at the geographic centre of Maritime Southeast Asia....

, but differs from them in its larger size and in the contracted lip.