Feather development grows, its spathe, which is where the rachis and vanes attach, continues to form. When spathe is finished developing, the calamus begins to form within the base of the spathe. The calamus is the quill of the feather, which is the bottom portion that stays mainly within the pulp cavity. From there, the feather is fully developed and will remain as such until molting occurs, causing it to fall off. Feathers fall off during molting, which occurs in the at different times through the year depending on the type of bird. Birds can molt for seasonal, reproductive and many other
Acorus calamus Acorus calamus Acorus calamus (also called sweet flag or calamus, among many common names) is a species of flowering plant, a tall wetland monocot of the family Acoraceae, in the genus "Acorus". Sweet flag is a herbaceous perennial, tall. In habit it resembles the iris, and has given its name to the flag iris, "I. pseudacorus". It consists of tufts of basal leaves that rise from a spreading rhizome. The leaves are erect yellowish-green, radical, with pink sheathing at their bases, sword-shaped, flat and narrow, tapering into a long, acute point, and have parallel veins. The leaves have smooth edges,