Rachis Rachis Rachis is a biological term for a main axis or "shaft" (from the Greek "ράχις, backbone, spine"). In vertebrates a "rachis" can refer to the series of articulated vertebrae, which encase the spinal cord. In this case the "rachis" usually forms the supporting axis of the body and is then called the spine or vertebral column. "Rachis" can also mean the central shaft of pennaceous feathers. In the gonad of the invertebrate nematode "C. elegans", a "rachis" is the central cell-free core or axis of the gonadal arm of both adult males and hermaphrodites where the germ cells have
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 The canes are sought-after and expensive, but have to a large extent been replaced by sticks made from plants, such as bamboos, rushes and osier willows.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).