is a term used to describe feather
-like or multi-divided features arising from both sides of a common axis in plant
structures, and comes from the Latin
for "feather". 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
, 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. 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
have pinnately divided leaves. Most species of ferns
have pinnate or more highly divided fronds
, and ferns the leaflets 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.
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.
In animals, pinnate is used to describe feather-like structures: