''Microtis'', commonly known as onion orchids or mignonette orchids is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of about 20

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

plant Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclud ...

s in the orchid

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 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 ...

. Onion orchids 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 ...

herbs 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 a single leaf at the base of the plant. They are similar to orchids in the genus ''

Prasophyllum ''Prasophyllum'', commonly known as leek orchids, is a genus of about 140 species of flowering plants in the orchid family, Orchidaceae and is found in Australia and New Zealand. The Australian species are found in all states but have not been re ...

'' in that they have an onion-like leaf. The flowers are small but often scented and attractive to their insect pollinators. They are widespread in

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area ...

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

and some

Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...

islands.

Description

Orchids in the genus ''Microtis'' are terrestrial,

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 ...

deciduous In the fields of horticulture and Botany, the term ''deciduous'' () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, aft ...

sympodial Sympodial growth is a bifurcating branching pattern where one branch develops more strongly than the other, resulting in the stronger branches forming the primary shoot and the weaker branches appearing laterally. A sympodium, also referred to a ...

herbs with a few inconspicuous, fine roots and an egg-shaped to almost spherical

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 ...

. The tuber often produces two tubers on the end of long, root-like

stolon In biology, stolons (from Latin '' stolō'', genitive ''stolōnis'' – "branch"), also known as runners, are horizontal connections between organisms. They may be part of the organism, or of its skeleton; typically, animal stolons are external s ...

s. There is a single, linear, cylindrical, onion-like leaf at the base of the plant. The leaf resembles that of the closely related genus ''

'' except that is entirely green (usually red at the base in ''Prasophyllum'') and exudes clear

mucilage Mucilage is a thick, gluey substance produced by nearly all plants and some microorganisms. These microorganisms include protists which use it for their locomotion. The direction of their movement is always opposite to that of the secretion of m ...

when damaged. The

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. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed o ...

is a

raceme A raceme ( or ) or racemoid is an unbranched, indeterminate type of inflorescence bearing flowers having short floral stalks along the shoots that bear the flowers. The oldest flowers grow close to the base and new flowers are produced as the s ...

with a few to many

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 " ...

green

flower A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechani ...

s spirally arranged on a flowering stem. Each flower has a short stalk with a small

bract In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis or cone scale. Bracts are usually different from foliage leaves. They may be smaller, larger, or of ...

near its base. The broad

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 sharp-pointed, dished on the lower side and forms a horizontal 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 are similar to, but much narrower than the dorsal sepal. The

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 smaller than the sepals, thin and are spread below or under the dorsal sepal. As is usual in orchids, one petal is highly modified as the central labellum. The labellum is egg-shaped to oblong and hangs or is curved against the ovary. The sexual parts of the flower are fused to the

, which is shaped like half a cylinder. Flowering time depends on the climatic region where the species is found and the fruit that follows flowering is a non-fleshy,

dehiscent Dehiscence is the splitting of a mature plant structure along a built-in line of weakness to release its contents. This is common among fruits, anthers and sporangia. Sometimes this involves the complete detachment of a part; structures that op ...

capsule containing up to 500 seeds.

Taxonomy and naming

The genus ''Microtis'' was first formally described by Robert Brown in 1810 and the description was published in ''

Prodromus Florae Novae Hollandiae ''Prodromus Florae Novae Hollandiae et Insulae Van Diemen'' (Prodromus of the Flora of New Holland and Van Diemen's Land) is a flora of Australia written by botanist Robert Brown and published in 1810. Often referred to as ''Prodromus Flora Novae ...

''. Brown described five species at the time ('' M. parviflora'', '' M. rara'', '' M. media'', '' M. alba'' and '' M. pulchella'') but did not nominate a

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

. The name ''Microtis'' 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 ...

words ''mikros'' (μικρός) meaning "small" and ''ous'', genitive ''ōtos'' (οὖς, genitive ὠτός) meaning "ear",Backer, C.A. (1936). ''Verklarend woordenboek der wetenschappelijke namen van de in Nederland en Nederlandsch-Indië in het wild groeiende en in tuinen en parken gekweekte varens en hoogere planten'' (Edition Nicoline van der Sijs). referring to the small, ear-like appendages on the column.

Distribution and habitat

Onion orchids are widespread in temperate areas of Australia and in sub-tropical

Queensland ) , nickname = Sunshine State , image_map = Queensland in Australia.svg , map_caption = Location of Queensland in Australia , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , established_ ...

, occurring in all states but not the

Northern Territory The Northern Territory (commonly abbreviated as NT; formally the Northern Territory of Australia) is an states and territories of Australia, Australian territory in the central and central northern regions of Australia. The Northern Territory ...

. ''

Microtis parviflora ''Microtis parviflora'', commonly known as the slender onion-orchid, is a species of orchid which is Indigenous (ecology), native to Australia and New Zealand. It occurs in all states of Australia but is not known from the Northern Territory and ...

'' and '' M. unifolia'' are the most widely distributed species and also occur on both main islands of

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

and as far south as Stewart and possibly

Auckland Auckland (pronounced ) ( mi, Tāmaki Makaurau) is a large metropolitan city in the North Island of New Zealand. The List of New Zealand urban areas by population, most populous urban area in the country and the List of cities in Oceania by po ...

Islands as well as

New Caledonia ) , anthem = "" , image_map = New Caledonia on the globe (small islands magnified) (Polynesia centered).svg , map_alt = Location of New Caledonia , map_caption = Location of New Caledonia , mapsize = 290px , subdivision_type = Sovereign st ...

, and

Norfolk Norfolk () is a ceremonial and non-metropolitan county in East Anglia in England. It borders Lincolnshire to the north-west, Cambridgeshire to the west and south-west, and Suffolk to the south. Its northern and eastern boundaries are the No ...

, Lord Howe and the

Kermadec Islands The Kermadec Islands ( mi, Rangitāhua) are a subtropical island arc in the South Pacific Ocean northeast of New Zealand's North Island, and a similar distance southwest of Tonga. The islands are part of New Zealand. They are in total are ...

in the western Pacific. These two species are also found in

Malaysia Malaysia ( ; ) is a country in Southeast Asia. The federation, federal constitutional monarchy consists of States and federal territories of Malaysia, thirteen states and three federal territories, separated by the South China Sea into two r ...

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania between the Indian and Pacific oceans. It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Guine ...

, the

Philippines The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...

Taiwan Taiwan, officially the Republic of China (ROC), is a country in East Asia, at the junction of the East and South China Seas in the northwestern Pacific Ocean, with the People's Republic of China (PRC) to the northwest, Japan to the nort ...

, southern

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

, the

Ryukyu Islands The , also known as the or the , are a chain of Japanese islands that stretch southwest from Kyushu to Taiwan: the Ōsumi, Tokara, Amami, Okinawa, and Sakishima Islands (further divided into the Miyako and Yaeyama Islands), with Yonaguni ...

and possibly on the

Chinese Chinese can refer to: * Something related to China * Chinese people, people of Chinese nationality, citizenship, and/or ethnicity **''Zhonghua minzu'', the supra-ethnic concept of the Chinese nation ** List of ethnic groups in China, people of va ...

mainland. They usually grow in areas that are wet in winter or in areas of high rainfall.

Ecology

Disease

The leaves of onion orchids are susceptible to fungal disease and most leaves appear to have some damage. The rust '' Uromyces microtidis'' has been identified as a

pathogen In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ ...

Pollination

''Microtis'' flowers are insect pollinated. For some species, the insect is a small wasp from a species of

Ichneumonidae The Ichneumonidae, also known as the ichneumon wasps, Darwin wasps, or ichneumonids, are a family (biology), family of parasitoid wasps of the insect order Hymenoptera. They are one of the most diverse groups within the Hymenoptera with roughly 2 ...

Braconidae The Braconidae are a family of parasitoid wasps. After the closely related Ichneumonidae, braconids make up the second-largest family in the order Hymenoptera, with about 17,000 recognized species and many thousands more undescribed. One analysis ...

. Pollination of orchids by ants is rare because the mouthparts of ants usually have antibiotic secretions which damage pollen grains. However, several species of ''Microtis'', including ''M. parviflora'' are pollinated by wingless worker ants from the genera ''

Iridomyrmex ''Iridomyrmex'' is a genus of ants called rainbow ants (referring to their blue-green iridescent sheen) first described by Austrian entomologist Gustav Mayr in 1862. He placed the genus in the subfamily Dolichoderinae of the family Formicida ...

'' (Family

Dolichoderinae Dolichoderinae is a subfamily of ants, which includes species such as the Argentine ant (''Linepithema humile''), the erratic ant, the odorous house ant, and the cone ant. The subfamily presents a great diversity of species throughout the world ...

), '' Meranops'' (Family

Myrmeciinae Myrmeciinae is a subfamily of the Formicidae, ants once found worldwide but now restricted to Australia and New Caledonia. This subfamily is one of several ant subfamilies which possess gamergates, female worker ants which are able to mate and ...

) and ''

Rhytidoponera ''Rhytidoponera'' is a large genus of ants in the subfamily Ectatomminae. The genus is known from Australia and Melanesia, with New Caledonia as the most eastern limit. Some ''Rhytidoponera'' species have both winged alate queens and gamergate ...

'' (Family

Ponerinae Ponerinae is a subfamily of ants in the Poneromorph subfamilies group, with about 1,600 species in 47 extant genera, including ''Dinoponera gigantea'' - one of the world's largest species of ant. Mated workers have replaced the queen as the fun ...

), having been attracted by nectar secreted from the base of the labellum.

Autogamy

Autogamy Autogamy, or self-fertilization, refers to the fusion of two gametes that come from one individual. Autogamy is predominantly observed in the form of self-pollination, a reproductive mechanism employed by many flowering plants. However, species o ...

has been observed in several species of onion orchid. In some cases, the pollen grains fall onto the stigma and germinate but in others, including in some populations of ''M. parvifolia'', if the flowers have not been cross-pollinated, the stigma grows upwards until it contacts the

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 ...

, so that seed is always produced.

Species

The taxonomy of ''Microtis'' has been confused ever since Robert Brown first described the genus. He did not include ''Ophrys unifolia''

G.Forst. Johann George Adam Forster, also known as Georg Forster (, 27 November 1754 – 10 January 1794), was a German naturalist, ethnologist, travel writer, journalist and revolutionary. At an early age, he accompanied his father, Johann Reinhold F ...

(1786) and ''Epipactis porrifolia'' Sw. (1800) and these names were used by later authors, although now recognised as ''Microtis media''. The small size of the flowers and their tendency to change when dried as herbarium species led to further confusion. * ''

Microtis alba ''Microtis alba'', commonly known as the white mignonette orchid or slender onion-orchid, is a species of orchid endemic to the south-west of Western Australia. It has a single hollow, onion-like leaf and up to sixty small, green and white flowe ...

'' R.Br. (1810) – white mignonette orchid ( SW Australia) * '' Microtis alboviridis'' R.J.Bates (2008) – scented mignonette orchid (SW Australia) * '' Microtis angusii'' D.L.Jones (1996) – Mona Vale onion orchid (New South Wales) * '' Microtis arenaria'' Lindl. (1840) – notched onion orchid (south-east Australia) * '' Microtis atrata'' Lindl. (1840) – swamp mignonette orchid (southern Australia) * '' Microtis brownii'' Rchb.f. (1871) – sweet mignonette orchid (SW Australia) * '' Microtis cupularis'' (D.L.Jones & G.Brockman) A.P.Br. (2005) – cupped mignonette orchid (SW Australia) * '' Microtis eremaea'' R.J.Bates (1996) – slender mignonette orchid (SW Australia) * '' Microtis eremicola'' (R.J.Bates) D.L.Jones & M.A.Clem. (1996) – desert mignonette orchid (SW Australia) * '' Microtis familiaris'' R.J.Bates (1990) – coastal mignonette orchid (SW Australia) * '' Microtis globula'' R.J.Bates (1984) – globular mignonette orchid (SW Australia) * '' Microtis gracilenta'' R.J.Bates (2015) (South Australia) * '' Microtis graniticola'' R.J.Bates, (1984) – globular mignonette orchid (SW Australia) * '' Microtis media'' R.Br. (1810) (SW Australia) ** ''Microtis media'' subsp. ''densiflora'' (Benth.) R.J.Bates, (1990) – dense mignonette orchid (SW Australia) ** ''Microtis media'' subsp. R.Br. ''media'' – common mignonette orchid (SW Australia) * '' Microtis oblonga'' R.S.Rogers (1923) – sweet onion orchid (SE Australia) * '' Microtis oligantha'' L.B.Moore, (1968) – small onion orchid (New Zealand) * '' Microtis orbicularis'' R.S.Rogers (1907) – dark mignonette orchid (southern Australia) * ''

'' R.Br. (1810) – slender onion orchid (all Australian states) * '' Microtis pulchella'' R.Br. (1810) – beautiful mignonette orchid (SW Australia) * '' Microtis quadrata'' (R.J.Bates) D.L.Jones & M.A.Clem. (1996) – south coast mignonette orchid (SW Australia) * '' Microtis rara'' R.Br., Prodr. (1810) – scented onion orchid (all Australian states) * ''

Microtis unifolia ''Microtis unifolia'', commonly known as the common onion orchid, is a species of orchid occurring from south China to Japan, Malesia, and Australasia to the Southwest Pacific. It has a single green leaf and up to one hundred small green or yell ...

'' (G.Forst.) Rchb.f. (1871) – common onion orchid (widespread from China, Japan, Philippines, Indonesia, Australia, New Zealand)

Use in horticulture

Most ''Microtis'' are very easy to grow, and readily volunteer themselves in other pots. Onion orchids are often found in gardens around

Melbourne Melbourne ( ; Boonwurrung/Woiwurrung: ''Narrm'' or ''Naarm'') is the capital and most populous city of the Australian state of Victoria, and the second-most populous city in both Australia and Oceania. Its name generally refers to a met ...

from wind-born seed.

Gallery

Image:Microtis media.jpg,

Franz Bauer __NOTOC__ Franz Andreas Bauer (later Francis) (14 March 1758 – 11 December 1840) was an Austrian microscopist and botanical artist. Born in Feldsberg, Lower Austria (now Valtice, Czech Republic), he was the son of Lucas Bauer (died 1761), cou ...

's 1835 illustration of '' Microtis media'' from ''

Curtis's Botanical Magazine ''The Botanical Magazine; or Flower-Garden Displayed'', is an illustrated publication which began in 1787. The longest running botanical magazine, it is widely referred to by the subsequent name ''Curtis's Botanical Magazine''. Each of the issue ...

'' Image:Microtis parviflora - Flickr 003.jpg, ''

'' (habit) Image:Microtis unifolia nirabarn01.JPG, ''

'',

Tanabe, Wakayama is a city located in Wakayama Prefecture, Japan. , the city had an estimated population of 70,972 in 35076 households and a population density of 69 persons per km². The total area of the city is . Tanabe is the second largest city in Wakayama ...

, Japan Image:Microtis unfolia nirabarn00.JPG, '' M. unifolia'' known as Nirabaran in Japan

References

* *

External links

* *
New Zealand Native orchid group
{{Taxonbar, from=Q3241818 Diurideae genera