Pennaceous feather Pennaceous feather The pennaceous feather is a type of feather present in most modern birds and in some other species of maniraptoriform dinosaurs. A pennaceous feather has a stalk or quill. Its basal part, called a "calamus", is embedded in the skin. The calamus is hollow and has pith formed from the dry remains of the feather pulp, and the calamus opens below by an "inferior umbilicus" and above by a "superior umbilicus". The stalk above the calamus is a solid "rachis" having an umbilical groove on its underside. Pennaceous feathers have a rachis with "vanes" or "vaxillum " spreading
Acorus calamus β-asarone is 2,4,5-trimethoxycinnamic acid, a derivative which is not a carcinogen. 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,