A samara (, ) is a winged

achene An achene (; ), also sometimes called akene and occasionally achenium or achenocarp, is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate (formed from one carpel) and indehiscent (they do not o ...

, a type of

fruit In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering. Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in partic ...

in which a flattened wing of fibrous, papery tissue develops from the ovary wall. A samara is a simple dry fruit, and is indehiscent (not opening along a seam). The shape of a samara enables the wind to carry the seed farther away from the tree than regular seeds would go, and is thus a form of anemochory. In some cases the seed is in the centre of the wing, as in the elms (genus ''Ulmus''), the hoptree (''

Ptelea trifoliata ''Ptelea trifoliata'', commonly known as common hoptree, wafer ash, stinking ash, and skunk bush, is a species of flowering plant in the citrus family ( Rutaceae). It is native to North America, where it is found in Canada, Mexico, and the Unit ...

''), and the bushwillows (genus '' Combretum''). In other cases the seed is on one side, with the wing extending to the other side, making the seed

autorotate For fixed-wing aircraft, autorotation is the tendency of an aircraft in or near a stall to roll spontaneously to the right or left, leading to a spin (a state of continuous autorotation).Clancy, L.J., ''Aerodynamics'', Sections 16.48 and 16.49 ...

as it falls, as in the

maple ''Acer'' () is a genus of trees and shrubs commonly known as maples. The genus is placed in the family Sapindaceae.Stevens, P. F. (2001 onwards). Angiosperm Phylogeny Website. Version 9, June 2008 nd more or less continuously updated since h ...

s (genus '' Acer'') and ash trees (genus '' Fraxinus''). There are also single-wing samara such as mahogany (genus Swietenia) which have a shape that enables fluttering. Some species that normally produce paired samaras, such as '' Acer pseudoplatanus'', can also produce them in groups of three or four. File:TripleSycamoreSamara.png, Unusual group of three samaras of sycamore maple ('' Acer pseudoplatanus''. Normally, they are in pairs.) File:Starr_040601-0006_Fraxinus_uhdei.jpg, Seeds of the tropical ash ('' Fraxinus uhdei'') File:Ptelea_trifoliata_20050606_635_part.jpg, The hoptree (''

'') File:Ulmus-pumila-samaras.jpg, The Siberian elm ('' Ulmus pumila'')

In culture

A samara is sometimes called a ''key'' and is often referred to as a '' wingnut'', ''

helicopter A helicopter is a type of rotorcraft in which lift and thrust are supplied by horizontally spinning rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forward, backward and laterally. These attribu ...

'', '' whirlybird'', '' whirligig'', ''polynose'', or, in the north of England, a '' spinning jenny''. During the autumn months, they are a popular source of amusement for children (and adults) who enjoy tossing them in the air and watching them spin to the ground.

In culture

References

Further reading