''Zeuxine exilis'', commonly known as Ridley's jewel orchid or the slender jewel orchid, is a species of

orchid Orchids are plants that belong to the family Orchidaceae (), a diverse and widespread group of flowering plants with blooms that are often colourful and fragrant. Along with the Asteraceae, they are one of the two largest families of flowering ...

that is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

Christmas Island Christmas Island, officially the Territory of Christmas Island, is an Australian external territory comprising the island of the same name. It is located in the Indian Ocean, around south of Java and Sumatra and around north-west of the ...

where it grows in rainforest. It has three or four egg-shaped leaves and up to thirty small, dull reddish flowers crowded along a thin, hairy flowering stem. It was first recorded in 1904 but was not seen again until 2009.

Description

''Zeuxine exilis'' is a

terrestrial Terrestrial refers to things related to land or the planet Earth. Terrestrial may also refer to: * Terrestrial animal, an animal that lives on land opposed to living in water, or sometimes an animal that lives on or near the ground, as opposed to ...

tuber Tubers are a type of enlarged structure used as storage organs for nutrients in some plants. They are used for the plant's perennation (survival of the winter or dry months), to provide energy and nutrients for regrowth during the next growing ...

ous,

perennial A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wide ...

herb In general use, herbs are a widely distributed and widespread group of plants, excluding vegetables and other plants consumed for macronutrients, with savory or aromatic properties that are used for flavoring and garnishing food, for medicinal ...

with three or four light green, lance-shaped leaves, long and wide. Between ten and thirty

resupinate Resupination is derived from the Latin word ''resupinus'', meaning "bent back with the face upward" or "on the back". "Resupination" is the noun form of the adjective "resupine" which means "being upside-down, supine or facing upward". The word " ...

, dull reddish flowers with white

petal Petals are modified Leaf, leaves that surround the reproductive parts of flowers. They are often advertising coloration, brightly colored or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''c ...

s, about long and wide are crowded on a thin, hairy flowering stem tall. The outside surface of the flowers is hairy. The

dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage * Dorsal co ...

sepal A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 The term ''sepalum'' was coined b ...

is about long, wide and overlaps the petals forming a hood over the

column A column or pillar in architecture and structural engineering is a structural element that transmits, through compression, the weight of the structure above to other structural elements below. In other words, a column is a compression member. ...

. The

lateral Lateral is a geometric term of location which may refer to: Healthcare *Lateral (anatomy), an anatomical direction *Lateral cricoarytenoid muscle *Lateral release (surgery), a surgical procedure on the side of a kneecap Phonetics *Lateral cons ...

sepals and petals are about long and wide with the lateral sepals spreading apart from each other. The labellum is white with a yellow centre, about long, wide with two lobes on the end that have wavy edges. Flowering occurs from July to September.

Taxonomy and naming

''Zeuxine exilis'' was first formally described in 1906 by Dr Henry Ridley and the description was published in the Journal of the Straits Branch of the Royal Asiatic Society. The

specific epithet In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

(''exilis'') is a

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

word meaning "thin" or "slender".

History of rediscovery

The rugged terrain on Christmas Island deterred early naturalists from surveying much of island.

Charles William Andrews Charles William Andrews (30 October 1866 – 25 May 1924) F.R.S., was a British palaeontologist whose career as a vertebrate paleontologist, both as a curator and in the field, was spent in the services of the British Museum, Department of Ge ...

, a British

palaeontologist Paleontology (), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (roughly 11,700 years before present). It includes the study of fossi ...

spent ten months on the island in 1897 and 1898 and although he collected several orchids, did not find ''Z. exilis''. In October 1904, Henry Ridley, the first director of the

Singapore Botanic Gardens The Singapore Botanic Gardens is a -year-old tropical garden located at the fringe of the Orchard Road shopping district in Singapore. It is one of three gardens, and the only tropical garden, to be honoured as a UNESCO World Heritage Site. Th ...

made his second, longer visit and crossed the island, including the upper plateau where he collected the orchid he later named ''Z. exilis'', on the 18th of that month. He noted "centre of the island, among ferns not rare." The species was then not officially recorded for over a century and in the third Christmas Island National Park Management Plan (2002) it was considered "possibly extinct". Other botanists, including Dulcie Alicia Powell and David J. Du Puy made collections on the island in the 1980s and 1990s without locating ''Z. exilis''. Then in 2009 it was found and collected by visiting research scientist Peter Green and the discovery was confirmed by Mark Clements.

Distribution and habitat

Ridley's jewel orchid is endemic to Christmas Island where it grows in litter on the floor of rainforest.

References

{{Taxonbar, from=Q766303 exilis Endemic flora of Christmas Island Plants described in 1906 Taxa named by Henry Nicholas Ridley