Pinnation

A simple pinnate (unipinnate) frond of the fern Blechnum appendiculatum.

Pinnation (also called pennation) is the arrangement of feather-like or multi-divided features arising from both sides of a common axis. Pinnation occurs in biological morphology, in crystals,[1] such as some forms of ice or metal crystals,[2][3] and in patterns of erosion or stream beds.[4]

The term derives from the Latin word pinna meaning "feather", "wing", or "fin". A similar concept is "pectination", which is a comb-like arrangement of parts (arising from one side of an axis only). Pinnation is commonly referred to in contrast to "palmation", in which the parts or structures radiate out from a common point. The terms "pinnation" and "pennation" are cognate, and although they are sometimes used distinctly, there is no consistent difference in the meaning or usage of the two words.[5][6]

  1. ^ Nicholas Eastaugh, Valentine Walsh, Tracey Chaplin, Ruth Siddall. Pigment Compendium: A Dictionary of Historical Pigments. Butterworth-Heinemann 2008. ISBN 978-0-7506-8980-9.
  2. ^ Charles Seymour Wright, Raymond Edward Priestley. Glaciology. Harrison and Sons, for the Committee of the Captain Scott Arctic Fund. 1922.
  3. ^ Journal of the Electrochemical Society, Volume 100, 1953, page 165: "The zinc is recovered electrolytically as 'flake' powder consisting of pinnate crystals."
  4. ^ Ravi P. Gupta. Remote Sensing Geology. Springer 2003. ISBN 978-3-540-43185-5.
  5. ^ Collocott, T. C., ed. (1974). Chambers Dictionary of science and technology. Edinburgh: W. and R. Chambers. ISBN 0-550-13202-3.
  6. ^ Jackson, Benjamin, Daydon; A Glossary of Botanic Terms with their Derivation and Accent. Gerald Duckworth & Co. London, 4th ed 1928.