Specimens of Archaeopteryx The end of the feather has an obtuse angle of 110°, while the barbs branch off from the rachis at an angle of around 25°. The barbs branch noticeably into barbules, as in the feathers of modern birds. The base of the feather consists of plumulaceous barbs which are unconnected to one another and result in a down-like appearance. This tuft of down led Griffiths to conclude that "Archaeopteryx" might have been endothermic in that it implies the use of thermal insulation. The feather is clearly asymmetrical, which has been interpreted by many scientists to be a clear indication of
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,