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
Calamus rotang plants. It has pinnate, alternate leaves, 60–80 cm long, armed with two rows of spines on the upper face. The plants are dioecious, and flowers are clustered in attractive inflorescences, enclosed by spiny spathes. The edible fruits are top-shaped, covered in shiny, reddish-brown imbricate scales, and exude an astringent red resin known medicinally and commercially as "Dragon's blood". The canes are sought-after and expensive, but have to a large extent been replaced by sticks made from plants, such as bamboos, rushes and osier willows. Calamus rotang Calamus rotang is a plant species native to India, Sri Lanka and Myanmar (Burma).