''Caleana'', commonly known as duck orchids, is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

s in the orchid family,

Orchidaceae Orchids are plants that belong to the family (biology), family Orchidaceae (), a diverse and widespread group of flowering plants with blooms that are often colourful and fragrant. Orchids are cosmopolitan distribution, cosmopolitan plants that ...

that is found in

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

and

New Zealand New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...

. The Australian species are found in all states but have not been recorded in the

Northern Territory The Northern Territory (abbreviated as NT; known formally as the Northern Territory of Australia and informally as the Territory) is an states and territories of Australia, Australian internal territory in the central and central-northern regi ...

. Duck orchids have a single leaf and one or a few, dull-coloured, inconspicuous flowers. Most species are found in

Western Australia Western Australia (WA) is the westernmost state of Australia. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to the south, the Northern Territory to the north-east, and South Australia to the south-east. Western Aust ...

but one species ('' C. major'') occurs in eastern

and one ('' C. minor'') occurs in eastern Australia and

. Orchids in this genus as well as the hammer orchids (''

Drakaea ''Drakaea'' is a genus of 10 species in the plant family Orchidaceae commonly known as hammer orchids. All ten species occur only in the south-west of Western Australia. Hammer orchids are characterised by an insectoid labellum that is attach ...

'') are pollinated by male thynnid wasps.

Description

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

perennial In horticulture, the term perennial ('' per-'' + '' -ennial'', "through the year") is used to differentiate a plant from shorter-lived annuals and biennials. It has thus been defined as a plant that lives more than 2 years. The term is also ...

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 Leaf, leaves, usually in the autumn; to the shedding of petals, aft ...

sympodial In botany, 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, als ...

herbs usually with a few inconspicuous, fine roots and a dark red, oval-shaped,

tuber Tubers are a type of enlarged structure that plants use as storage organs for nutrients, derived from stems or roots. Tubers help plants perennate (survive winter or dry months), provide energy and nutrients, and are a means of asexual reproduc ...

. Replacement tubers called "droppers" form at the end of long root-like

stolon In biology, a stolon ( from Latin ''wikt:stolo, stolō'', genitive ''stolōnis'' – "branch"), also known as a runner, is a horizontal connection between parts of an organism. It may be part of the organism, or of its skeleton. Typically, animal ...

s. A single linear to egg-shaped leaf long develops near the base of the plant during the growing season and withers late in the flowering season. The leaf is folded lengthwise and often has purple markings. The flowering stem is wiry, dull brownish maroon and bears one to a few flowers each on a stalk long, each with a small leaf-like

bract In botany, a bract is a modified or specialized leaf, associated with a reproductive structure such as a flower, inflorescence axis or cone scale. Bracts are usually different from foliage leaves in size, color, shape or texture. They also lo ...

. The flowers are non-resupinate and

glabrous Glabrousness () is the technical term for a lack of hair, down, setae, trichomes, or other such covering. A glabrous surface may be a natural characteristic of all or part of a plant or animal, or be due to loss because of a physical condition, ...

. 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 The fus ...

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 Etymology The term ''sepalum'' ...

and the two

lateral Lateral is a geometric term of location which may also refer to: Biology and healthcare * Lateral (anatomy), a term of location meaning "towards the side" * Lateral cricoarytenoid muscle, an intrinsic muscle of the larynx * Lateral release ( ...

petal Petals are modified leaves that form an inner whorl surrounding the reproductive parts of flowers. They are often brightly coloured or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''corol ...

s are similar in size and are narrow linear in shape with pointed or club-shaped ends. The dorsal sepal points downwards and is pressed against 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

sepals and two petals usually spread obliquely downwards and sideways. The dorsal sepal and petals are attached to the base of the column where it joins to the ovary. As is usual in orchids, one

is highly modified as the central labellum. Duck orchids have an unusual, insect-like labellum which is attached to the rest of the flower by a sensitive stalk which holds the labellum above the flower in the "set" position. The labellum is attached to the

by a flexible "claw" which bends under the weight of a

pollinating Pollination is the transfer of pollen from an anther of a plant to the stigma of a plant, later enabling fertilisation and the production of seeds. Pollinating agents can be animals such as insects, for example bees, beetles or butterflies; birds ...

wasp A wasp is any insect of the narrow-waisted suborder Apocrita of the order Hymenoptera which is neither a bee nor an ant; this excludes the broad-waisted sawflies (Symphyta), which look somewhat like wasps, but are in a separate suborder ...

. The

has broad wings and when the labellum is touched, it rapidly turns down, trapping a visiting insect between the labellum and column wings so that the insect comes into contact with the sexual parts of the column. The labellum is flask-shaped, narrowing near the end with the narrow end covered with small raised calli or

glands A gland is a Cell (biology), cell or an Organ (biology), organ in an animal's body that produces and secretes different substances that the organism needs, either into the bloodstream or into a body cavity or outer surface. A gland may also funct ...

which are usually black, but may be maroon or greenish. In some species the calli may cover a greater part, or even all of the labellum (as in '' P. minor''). Glands on the labellum emit

pheromone A pheromone () is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavio ...

s which are sexual attractants for male thynnid wasps. Flowering occurs in spring in most species and is followed by the fruit which 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 ''Caleana'' was first formally described in 1810 by

Robert Brown Robert Brown may refer to: Robert Brown (born 1965), British Director, Animator and author Entertainers and artists * Washboard Sam or Robert Brown (1910–1966), American musician and singer * Robert W. Brown (1917–2009), American printmaker ...

and the description was published in ''

Prodromus Florae Novae Hollandiae et Insulae Van Diemen ''Prodromus Florae Novae Hollandiae et Insulae Van Diemen'' (Prodromus of the Flora of New Holland and Van Diemen's Land) is a book by the botanist Robert Brown Robert Brown may refer to: Robert Brown (born 1965), British Director, Animator and ...

''. The name ''Caleana'' honours

George Caley George Caley (10 June 1770 – 23 May 1829) was an English botanist and explorer, active in Australia for the majority of his career. Early life Caley was born in Craven District, Craven, Yorkshire, England, the son of a horse-dealer. He was ed ...

. There has been disagreement about the classification of this

and its relationship with ''Paracaleana''. In 1989 Mark Clements noted that none of the characters used to separate ''Paracaleana'' from ''Caleana'' is "sufficiently significant" to maintain two genera. A recent (2014) paper reports that recent molecular studies suggest that ''Caleana'' and ''Paracaleana'' are congeneric. However, the

Western Australian Herbarium The Western Australian Herbarium is the state Herbarium, situated in Perth, the capital of Western Australia. It houses a collection of more than 845,000 dried specimens of plants, algae, bryophytes (mosses, liverworts and hornworts), lichens, fu ...

and several recent field guides to the orchids of Western Australia accept ''Paracaleana''.

Species list

The following is a list of the species of ''Caleana'' accepted by the World Checklist of Selected Plant Families as at April 2018. *'' Caleana alcockii'' (

Hopper Hopper or hoppers may refer to: Places * Hopper, Illinois * Hopper, West Virginia * Hopper, a mountain and valley in the Hunza–Nagar District of Pakistan * Hopper (crater), a crater on Mercury People * Hopper (surname) Insects * Hopper, the ...

& A.P.Br.) M.A.Clem. – Alcock's duck orchid (

) *'' Caleana brockmanii'' (Hopper & A.P.Br.) M.A.Clem. – Brockman's duck orchid (Western Australia) *''

Caleana disjuncta ''Caleana disjuncta'', commonly known as the little duck orchid, is a species of orchid that is found in Western Australia but with a few disjunct populations in Victoria and South Australia. It has a single smooth leaf and a single greenish ye ...

'' ( D.L.Jones) M.A.Clem. – little duck orchid (Western Australia),

South Australia South Australia (commonly abbreviated as SA) is a States and territories of Australia, state in the southern central part of Australia. With a total land area of , it is the fourth-largest of Australia's states and territories by area, which in ...

Victoria Victoria most commonly refers to: * Queen Victoria (1819–1901), Queen of the United Kingdom and Empress of India * Victoria (state), a state of Australia * Victoria, British Columbia, Canada, a provincial capital * Victoria, Seychelles, the capi ...

*'' Caleana dixonii'' (Hopper & A.P.Br.) M.A.Clem. – sandplain duck orchid (Western Australia) *'' Caleana gracilicordata'' (Hopper & A.P.Br.) M.A.Clem. – slender-leafed duck orchid (Western Australia) *'' Caleana granitica'' (Hopper & A.P.Br.) M.A.Clem. – granite duck orchid (Western Australia) *'' Caleana hortiorum'' (Hopper & A.P.Br.) M.A.Clem. – Hort's duck orchid (Western Australia) *'' Caleana lyonsii'' (Hopper & A.P.Br.) M.A.Clem. – midget duck orchid (Western Australia) *'' Caleana major'' R.Br. – large duck orchid (

New South Wales New South Wales (commonly abbreviated as NSW) is a States and territories of Australia, state on the Eastern states of Australia, east coast of :Australia. It borders Queensland to the north, Victoria (state), Victoria to the south, and South ...

Queensland Queensland ( , commonly abbreviated as Qld) is a States and territories of Australia, state in northeastern Australia, and is the second-largest and third-most populous state in Australia. It is bordered by the Northern Territory, South Austr ...

Tasmania Tasmania (; palawa kani: ''Lutruwita'') is an island States and territories of Australia, state of Australia. It is located to the south of the Mainland Australia, Australian mainland, and is separated from it by the Bass Strait. The sta ...

) *'' Caleana minor'' R.Br. – small duck orchid (

North Island of New Zealand The North Island ( , 'the fish of Māui', historically New Ulster) is one of the two main islands of New Zealand, separated from the larger but less populous South Island by Cook Strait. With an area of , it is the world's 14th-largest island ...

) *'' Caleana nigrita''

J.Drumm. James Drummond (late 1786 or early 1787 – 26 March 1863) was an Australian botanist and naturalist who was an early settler in Western Australia. Early life James Drummond was born in Inverarity, near Forfar, Angus, Scotland, the el ...

ex Lindl. – flying duck orchid (Western Australia) *'' Caleana parvula'' (Hopper & A.P.Br.) M.A.Clem. – Esperance duck orchid (Western Australia) *'' Caleana terminalis'' (Hopper & A.P.Br.) M.A.Clem. – smooth-billed duck orchid (Western Australia) *'' Caleana triens'' (Hopper & A.P.Br.) M.A.Clem. – broad-billed duck orchid (Western Australia)

Distribution and habitat

The Western Australian duck orchids usually grow in sandy soil near areas that are swampy in winter where they often grow with hare orchids ('' Leporella''), hammer orchids (''

'') and beak orchids ('' Pyrorchis''). '' Caleana major'' which occurs in eastern Australia and '' C. minor'' which is found in both eastern Australia and New Zealand grow in

woodland A woodland () is, in the broad sense, land covered with woody plants (trees and shrubs), or in a narrow sense, synonymous with wood (or in the U.S., the '' plurale tantum'' woods), a low-density forest forming open habitats with plenty of sunli ...

, damp

heath A heath () is a shrubland habitat found mainly on free-draining infertile, acidic soils and is characterised by open, low-growing woody vegetation. Moorland is generally related to high-ground heaths with—especially in Great Britain—a coole ...

shrubland and grassland, sometimes on rocky slopes or in gravelly soil or on road verges.

Ecology

Orchids in the genus ''Caleana'' are pollinated by male thynnid wasps which are attracted to the flower by

s. When a wasp lands on the labellum, in its attempt to

copulate Sexual intercourse (also coitus or copulation) is a sexual activity typically involving the insertion of the erect male penis inside the female vagina and followed by thrusting motions for sexual pleasure, reproduction, or both.Sexual inte ...

with it, the labellum is flipped downwards against the column. If the flower has not previously been visited,

pollinia A pollinium (: 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 milkwee ...

in the column will adhere to the insect's back. When that insect visits another duck orchid and the process is repeated, the transported pollinia will adhere to the stigma of the second flower and it will be pollinated.

References

External links

* {{Taxonbar, from=Q3291981 Diurideae genera Orchids of Australia Orchids of New Zealand Taxa named by Robert Brown (botanist, born 1773)