Rachis is an extension of a compound leaf or it can be main stem of a compound leaf.
Spine.
rachis
barb
A feather has a main shaft, called the rachis.
the rachis of a fern
the Rachis is the central part of the feather, Barbs branch of the Rachis, Barbules branch off the Barbs and Barbicels (Hooks) branch off the Barbsbarbules
is that rachis is (botany) the main shaft of either a compound leaf, head of grain, or fern frond while branch is the woody part of a tree arising from the trunk and usually dividing.
The rachis, the central shaft of a feather, has a lightweight yet sturdy structure that supports the vanes while allowing for flexibility and aerodynamic efficiency. Composed of a hollow, keratin-based material, it minimizes weight without sacrificing strength, enabling birds to achieve flight with agility. Additionally, its segmented design provides attachment points for barbs, which create the necessary surface area for lift and insulation. Overall, the rachis's structure is optimally adapted to enhance the feather's primary functions of flight and temperature regulation.
The sections of a compound leaf are known as leaflets. These leaflets are attached to a common stalk called a rachis. Compound leaves can be either pinnately compound, with the leaflets arranged along the rachis like a feather, or palmately compound, with the leaflets arranged like the fingers of a hand.
Contour feather is the largest feather of a bird. It has 7 basic part and they are the Calamus, Rachis, Vane, Barbs, Barbules, Hooklets, and the Afterfeather.
In woodapple the leaf is compound. It is generally trifoliate.
That is how a pyramid is defined!That is how a pyramid is defined!That is how a pyramid is defined!That is how a pyramid is defined!