Pinnate
Overview
 
Pinnate is a term used to describe feather-like or multi-divided features arising from both sides of a common axis in plant or animal structures, and comes from the Latin word pinna meaning "feather", "wing", or "fin". A similar term is pectinate, which refers to a comb-like arrangement of parts (arising from one side of an axis). The term contrasts somewhat with palmate
Leaf shape
In botany, leaf shape is characterised with the following terms :* Acicular : Slender and pointed, needle-like* Acuminate : Tapering to a long point...

, in which the parts or structures radiate out from a common point.

Botanically, the term describes an arrangement of discrete structures (such as leaflets, veins, lobes, branches, or appendages) arising at multiple points along a common axis.
Encyclopedia
Pinnate is a term used to describe feather-like or multi-divided features arising from both sides of a common axis in plant or animal structures, and comes from the Latin word pinna meaning "feather", "wing", or "fin". A similar term is pectinate, which refers to a comb-like arrangement of parts (arising from one side of an axis). The term contrasts somewhat with palmate
Leaf shape
In botany, leaf shape is characterised with the following terms :* Acicular : Slender and pointed, needle-like* Acuminate : Tapering to a long point...

, in which the parts or structures radiate out from a common point.

Plants

Botanically, the term describes 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
Rachis
Rachis is a biological term for a main axis or "shaft".-In zoology:In vertebrates a rachis can refer to the series of articulated vertebrae, which encase the spinal cord. In this case the rachis usually form the supporting axis of the body and is then called the spine or vertebral column...

are pinnately compound leaves. Many palm
Arecaceae
Arecaceae or Palmae , are a family of flowering plants, the only family in the monocot order Arecales. There are roughly 202 currently known genera with around 2600 species, most of which are restricted to tropical, subtropical, and warm temperate climates...

s (notably the feather palms) and most cycad
Cycad
Cycads are seed plants typically characterized by a stout and woody trunk with a crown of large, hard and stiff, evergreen leaves. They usually have pinnate leaves. The individual plants are either all male or all female . Cycads vary in size from having a trunk that is only a few centimeters...

s and grevillea
Grevillea
Grevillea is a diverse genus of about 360 species of evergreen flowering plants in the protea family Proteaceae, native to Australia, New Guinea, New Caledonia, and Sulawesi. It was named in honour of Charles Francis Greville. The species range from prostrate shrubs less than 0.5 m tall to trees...

s have pinnately divided leaves. Most species of fern
Fern
A fern is any one of a group of about 12,000 species of plants belonging to the botanical group known as Pteridophyta. Unlike mosses, they have xylem and phloem . They have stems, leaves, and roots like other vascular plants...

s have pinnate or more highly divided frond
Frond
The term frond refers to 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...

s, 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".

pinnatifid and pinnatipartite: leaves with pinnate lobes that are not discrete, remaining sufficiently connected to each other that they are not separate leaflets.

pinnatisect: cut all the way to the midrib or other axis, but with the bases of the pinnae not contracted to form discrete leaflets.

pinnate-pinnatifid: pinnate, with the pinnae being pinnatifid.

paripinnate: pinnately-compound leaves in which leaflets are born in pairs along the rachis without a single terminal leaflet; also called "even-pinnate".

imparipinnate: pinnately-compound leaves in which there is a lone terminal leaflet rather than a terminal pair of leaflets; also called "odd-pinnate".

bipinnate: pinnately compound leaves in which the leaflets are themselves pinnately-compound; also called "twice-pinnate".

tripinnate: pinnately compound leaves in which the leaflets are themselves bipinnate; also called "thrice-pinnate".

tetrapinnate: pinnately compound leaves in which the leaflets are themselves tripinnate.

unipinnate: solitary compound leaf with a row of leaflets arranged along each side of a common rachis
Rachis
Rachis is a biological term for a main axis or "shaft".-In zoology:In vertebrates a rachis can refer to the series of articulated vertebrae, which encase the spinal cord. In this case the rachis usually form the supporting axis of the body and is then called the spine or vertebral column...

.

Animals

In animals, pinnate is used to describe feather-like structures:
  • Some muscles can be unipinnate or bipinnate muscles
  • The fish, Platax pinnatus
    Platax pinnatus
    Platax pinnatus, also known as dusky batfish or red-faced batfish is a fish from the western Pacific that occasionally is kept in marine aquariums.-Anatomy and morphology:...

    , is known as the pinnate spadefish or pinnate batfish. Plus the "pinnate bird" is also covered in feathers that look like leaves.

Geomorphology

The term is also used to describe certain waterway systems in which all major tributary streams enter the main channels by flowing in one direction at an oblique angle.
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