Pinnation

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

Contents

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]

Plants

Botanically, pinnation is an arrangement of discrete structures (such as leaflets, veins, lobes, branches, or appendages) arising at multiple points along a common axis. For example, once-divided leaf blades having leaflets arranged on both sides of a rachis are pinnately compound leaves. Many palms (notably the feather palms) and most cycads and grevilleas have pinnately divided leaves. Most species of ferns have pinnate or more highly divided fronds, and in ferns, the leaflets or segments are typically referred to as "pinnae" (singular "pinna"). Plants with pinnate leaves are sometimes colloquially called "feather-leaved". Most of the following definitions are from Jackson's Glossary of Botanical Terms: [6]

Depth of divisions

Number of divisions

Iteration of divisions

Bipinnate leaves of species of palm in the genus Caryota Caryota bipinnate leaves IMG 5385.JPG
Bipinnate leaves of species of palm in the genus Caryota

The term pinnula (plural: pinnulae) is the Latin diminutive of pinna (plural: pinnae); either as such or in the Anglicised form: pinnule, it is differently defined by various authorities. Some apply it to the leaflets of a pinna, especially the leaflets of bipinnate or tripinnate leaves. [7] Others also or alternatively apply it to second or third order divisions of a bipinnate or tripinnate leaf. [8] It is the ultimate free division (or leaflet) of a compound leaf, or a pinnate subdivision of a multipinnate leaf.

Animals

In animals, pinnation occurs in various organisms and structures, including:

Geomorphology

Pinnation occurs in certain waterway systems in which all major tributary streams enter the main channels by flowing in one direction at an oblique angle.[ citation needed ]

Related Research Articles

<span class="mw-page-title-main">Frond</span> Collection of leaflets on a plant

A frond is a large, divided leaf. In both common usage and botanical nomenclature, the leaves of ferns are referred to as fronds and some botanists restrict the term to this group. Other botanists allow the term frond to also apply to the large leaves of cycads, as well as palms (Arecaceae) and various other flowering plants, such as mimosa or sumac. "Frond" is commonly used to identify a large, compound leaf, but if the term is used botanically to refer to the leaves of ferns and algae it may be applied to smaller and undivided leaves.

<i>Aralia spinosa</i> Species of tree

Aralia spinosa, commonly known as devil's walking stick, is a woody species of plant in the genus Aralia, family Araliaceae, native to eastern North America. The various names refer to the viciously sharp, spiny stems, petioles, and even leaf midribs. It has also been known as Angelica-tree.

<span class="mw-page-title-main">Rachis</span> Biological term for axis or shaft

In biology, a rachis is a main axis or "shaft".

<i>Attalea crassispatha</i> Species of palm

Attalea crassispatha is a palm which is endemic to southwest Haiti. The most geographically isolated member of the genus, it is considered a critically endangered species and has been called one of the rarest palms in the Americas.

This glossary of botanical terms is a list of definitions of terms and concepts relevant to botany and plants in general. Terms of plant morphology are included here as well as at the more specific Glossary of plant morphology and Glossary of leaf morphology. For other related terms, see Glossary of phytopathology, Glossary of lichen terms, and List of Latin and Greek words commonly used in systematic names.

<i>Asplenium bradleyi</i> Species of fern in the family Aspleniaceae

Asplenium bradleyi, commonly known as Bradley's spleenwort or cliff spleenwort, is a rare epipetric fern of east-central North America. Named after Professor Frank Howe Bradley, who first collected it in Tennessee, it may be found infrequently throughout much of the Appalachian Mountains, the Ozarks, and the Ouachita Mountains, growing in small crevices on exposed sandstone cliffs. The species originated as a hybrid between mountain spleenwort and ebony spleenwort ; A. bradleyi originated when that sterile diploid hybrid underwent chromosome doubling to become a fertile tetraploid, a phenomenon known as allopolyploidy. Studies indicate that the present population of Bradley's spleenwort arose from several independent doublings of sterile diploid hybrids. A. bradleyi can also form sterile hybrids with several other spleenworts.

<i>Alsophila borbonica</i> Species of fern

Alsophila borbonica, synonym Cyathea borbonica, is a tree fern endemic to Mauritius and Réunion. There are several natural forms and varieties.

Pterolobium membranulaceum is a flowering plant in the legume family, Fabaceae. The woody vine is endemic to secondary forest of the Philippines. Its general appearance is comparable to others of its genus, with bipinnate leaves and rufous samara fruit. The pubescent petiole and leaf rachis vary between 10 and 21 cm in length. The leaves carry 5 to 10 pairs of pinnae, with 6 to 8 pairs of oblong leaflets per pinna. The pubescent and loosely flowered inflorescences are borne on the side or tips of branches.

Asplenium × wherryi, known as Wherry's spleenwort, is a rare hybrid fern of the Appalachian Mountains. The sterile triploid offspring of mountain spleenwort (A. montanum) and Bradley's spleenwort (A. bradleyi), it is known from a few sites where those species grow together. First collected by Edgar T. Wherry in 1935, it was largely ignored until a new colony was found in 1961, and the species was named in his honor.

Myriopteris aemula, the Texas lip fern or rival lip fern, is a moderately-sized fern of Texas and Mexico, a member of the family Pteridaceae. Unlike many members of its genus, its leaves have a few hairs on upper and lower surfaces, or lack them entirely. One of the cheilanthoid ferns, it was usually classified in the genus Cheilanthes as Cheilanthes aemula until 2013, when the genus Myriopteris was again recognized as separate from Cheilanthes. It typically grows on limestone rock.

Argyrochosma connectens is a small cheilanthoid fern endemic to Sichuan, China. It is the only member of its genus known from Asia. Relatively rare, it is found growing in the crevices of limestone rocks in hot, dry valleys. The species was long classified in the genus Pellaea, but after a phylogenetic study in 2015 was transferred to Argyrochosma.

<i>Argyrochosma peninsularis</i> Species of fern in the family Pteridaceae

Argyrochosma peninsularis is a fern endemic to Baja California Sur. It grows in dry, rocky places. First described as a species in 1939, it was transferred to the new genus Argyrochosma in 1987, recognizing their distinctness from the "cloak ferns". A dusting of powdery material and the presence of occasional scales on the central axis of its leaves help distinguish it from related species.

Argyrochosma pallens is a fern endemic to Mexico. It has narrow, divided leaves with brown axes; the leaves are dusted with white powder above and coated in it below. First described as a species in 1956, it was transferred to the new genus Argyrochosma in 1987, recognizing their distinctness from the "cloak ferns".

Argyrochosma lumholtzii is a rare fern in the family Pteridaceae known from Sonora, Mexico. It is quite similar to Jones' false cloak fern, but has black leaf axes and a less highly divided leaf. First described as a species in 1939, honoring the explorer Carl Sofus Lumholtz, it was transferred to the new genus Argyrochosma in 1987, recognizing their distinctness from the "cloak ferns".

Argyrochosma palmeri is a fern endemic to Mexico. It has narrow, divided leaves with black axes; the leaves are coated in white powder below, and sparsely dusted or free of it above. First described as a species in 1887, it was transferred to the new genus Argyrochosma in 1987, recognizing their distinctness from the "cloak ferns".

Argyrochosma pilifera is a fern endemic to Mexico. It has lance-shaped, divided leaves with dark purple axes; the undersides of the leaves are coated in white powder. First described as a species in 1956, it was transferred to the new genus Argyrochosma in 1987, recognizing their distinctness from the "cloak ferns".

Anemia tabascana is a fern endemic to the state of Tabasco, Mexico. It grows on road banks on a single hill in Huimanguillo. Like other members of the genus, its leaves are pinnately divided into a single set of leaflets; in fertile leaves, the lowest pair of leaflets projects at right angles to the rest of the leaf and bears spores. The freely forking veins, which do not rejoin one another after forking, and sparse, rather than abundant, hairs on the leaf axes, distinguish it from similar species in the genus.

<i>Myriopteris rawsonii</i> Species of fern

Myriopteris rawsonii, formerly known as Cheilanthes rawsonii, is a perennial fern native to Namaqualand in Southern Africa. Like many other cheilanthoid ferns, it is adapted to dry conditions, bearing a thick layer of pale hairs on the underside of its pinnate-pinnatifid leaves. It is the only African representative of its clade of cheilanthoids, the otherwise American genus Myriopteris. It spends much of the year in a dried-out, dormant state, rehydrating and putting out new growth during winter rains. Its name honors the botanist and civil servant Sir Rawson W. Rawson.

<i>Gymnocarpium disjunctum</i> Species of fern

Gymnocarpium disjunctum is a species of fern in the family Cystopteridaceae, commonly known as Pacific oak fern, western oak fern, or Pacific oakfern.

Myriopteris chipinquensis is a fern endemic to Mexico, a member of the family Pteridaceae. One of the cheilanthoid ferns, it was classified in the genus Cheilanthes until 2013, when the genus Myriopteris was again recognized as separate from Cheilanthes. It grows in oak-pine forests of the Sierra Madre Oriental, often with the very similar and closely related Myriopteris tomentosa.

References

  1. Nicholas Eastaugh, Valentine Walsh, Tracey Chaplin, Ruth Siddall. "Pigment Compendium: A Dictionary of Historical Pigments". Pub: Butterworth-Heinemann 2008. ISBN   978-0-7506-8980-9
  2. Charles Seymour Wright, Raymond Edward Priestley. Glaciology. Pub: 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. Publisher: 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.{{cite book}}: |author= has generic name (help)
  6. 1 2 Jackson, Benjamin, Daydon; A Glossary of Botanic Terms with their Derivation and Accent; Published by Gerald Duckworth & Co. London, 4th ed 1928
  7. Chittenden, Fred J. Ed., Royal Horticultural Society Dictionary of Gardening, Oxford 1951
  8. Shastri, Varun. Dictionary of Botany. Publisher: Isha Books 2005. ISBN   978-8182052253