Feather development non-nervous. They have a tubular central shaft called the rachis; coming off either side of the rachis are the veins, which have a series of barbs with interlocking connections that are called barbules. The rachis and attached veins make up the spathe. The opposite of the rachis is the calamus, which anchors the feather to the body and is moved by attached dermal muscles. There are many different types of feathers that mostly follow this basic design with few variations based on evolutionary needs. Feathers are sometimes referred to as “elaborate reptile scales” just as birds are sometimes viewed as
Acorus calamus finger and has numerous coarse fibrous roots below it. The exterior is brown and the interior white. Sweet flag is native to India, central Asia, southern Russia and Siberia, and perhaps Eastern Europe. It also grows in China and Japan. It was introduced into Western Europe and North America for medicinal purposes. Habitats include edges of small lakes, ponds and rivers, marshes, swamps, and wetlands. In addition to "sweet flag" and "calamus" other common names include beewort, bitter pepper root, calamus root, flag root, gladdon, myrtle flag, myrtle grass, myrtle root, myrtle sedge, pine root, rat root, sea sedge, sweet