''Apostasia'', commonly known as grass orchids, is a genus of eight species of primitive

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 ...

s in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Orchidaceae. They are

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 ...

evergreen In botany, an evergreen is a plant which has foliage that remains green and functional through more than one growing season. This also pertains to plants that retain their foliage only in warm climates, and contrasts with deciduous plants, which ...

, grass-like plants, barely recognisable as orchids and are distributed in humid areas of the Himalayan region, China, India, Sri Lanka, Southeast Asia, New Guinea, and Queensland. They have many narrow leaves and small yellow or white, non-resupinate, star-like flowers usually arranged on a branched flowering stem.

Description

Plants in the genus ''Apostasia'' are evergreen, terrestrial, grass-like plants with a scaly

rhizome In botany and dendrology, a rhizome (; , ) is a modified subterranean plant stem that sends out roots and shoots from its nodes. Rhizomes are also called creeping rootstalks or just rootstalks. Rhizomes develop from axillary buds and grow hori ...

with a few roots that sometimes develop

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 ...

s. They have thin stems with many long, narrow, grass-like leaves spirally arranged around them. Small yellow or white, non-resupinate flowers are arranged on a short, often branching flowering stem. The three

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 ...

s and three

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 are all similar in size, shape and colour, unlike in more familiar orchids which usually have one petal modified as a labellum and often a

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 which differs from 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. The parts of 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. ...

are also different from those in other orchids, with three instead of two

stamen The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filame ...

s, which are separate from the

style Style is a manner of doing or presenting things and may refer to: * Architectural style, the features that make a building or structure historically identifiable * Design, the process of creating something * Fashion, a prevailing mode of clothing ...

. Moreover, the

pollen Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametophyt ...

grains are not adhering to each other in

pollinia A pollinium (plural pollinia) is a coherent mass of pollen grains in a plant that are the product of only one anther, but are transferred, during pollination, as a single unit. This is regularly seen in plants such as orchids and many species of mil ...

Taxonomy and naming

The genus ''Apostasia'' was first formally described in 1825 by

Carl Ludwig Blume Charles Ludwig de Blume or Karl Ludwig von Blume (9 June 1796, Braunschweig – 3 February 1862, Leiden) was a German-Dutch botanist. He was born at Braunschweig in Germany, but studied at Leiden University and spent his professional life wor ...

who published the description in ''Bijdragen tot de flora van Nederlandsch Indië''. The genus name ''Apostasia'' is derived from the

Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic peri ...

word ''apostasis'' meaning "defection" or "departure from", referring to the distinct features of this genus. The two genera in the subfamily ''

Apostasioideae Apostasioideae is one of the five subfamilies recognised within the orchid family, Orchidaceae. Only two genera, '' Neuwiedia'' and ''Apostasia'', and 15 species, are recognised within the Apostasioideae in contrast to the other orchid subfamili ...

'', ''Apostasia'' and ''

Neuwiedia ''Neuwiedia'' is a genus of primitive terrestrial orchids (family Orchidaceae), comprising 9 species native to China, Southeast Asia and certain Pacific Islands. The two genera in the subfamily ''Apostasioideae'', '' Apostasia'' and ''Neuwiedia' ...

'', differ from most other orchids in having three stamens. Recent studies suggest that the fifteen or so species in these two genera, although exhibiting "primitive" features, are "sister" genera rather than ancestors of other orchid families.

Distribution and habitat

Species in the genus ''Apostasia'' are found from north-eastern India,

Nepal Nepal (; ne, नेपाल ), formerly the Federal Democratic Republic of Nepal ( ne, सङ्घीय लोकतान्त्रिक गणतन्त्र नेपाल ), is a landlocked country in South Asia. It is mai ...

and

Bhutan Bhutan (; dz, འབྲུག་ཡུལ་, Druk Yul ), officially the Kingdom of Bhutan,), is a landlocked country in South Asia. It is situated in the Eastern Himalayas, between China in the north and India in the south. A mountainous ...

to southern Japan, and through Southeast Asia to New Guinea and northern Australia. Three species, one of which 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 ...

, are found in China and one is endemic to Queensland.

List of species

The following is a list of species of ''Apostasia'' recognised by the ''

World Checklist of Selected Plant Families The World Checklist of Selected Plant Families (usually abbreviated to WCSP) is an "international collaborative programme that provides the latest peer reviewed and published opinions on the accepted scientific names and synonyms of selected plan ...

'' as at August 2018: * '' Apostasia fogangica'' 2016 * '' Apostasia latifolia'' , 1889. * '' Apostasia nuda'' , 1830. * '' Apostasia odorata'' , 1825. * '' Apostasia parvula'' , 1906. * '' Apostasia ramifera'' , 1986. * '' Apostasia shenzhenica'' , 2011. * ''

Apostasia wallichii ''Apostasia wallichii'', commonly known as the yellow grass orchid, is a species of orchid that is Indigenous (ecology), native to India, Japan, China, Southeast Asia, New Guinea and northern Australia. It has many arching, dark green, grass-lik ...

'' , 1830.

References

{{Taxonbar, from=Q133739 Terrestrial orchids Orchids of India Orchids of China Orchids of Japan Orchids of Thailand Orchids of Queensland Orchids of Malaysia Orchids of Indonesia Orchids of the Philippines Orchids of New Guinea Orchid genera