Calamus maximus climbs on tall trees. The old stems are hard, green or occasionally pale yellow green in color, 6.3 cm thick. The branches are alternating, about 7.6 – 12.7 m apart, the lower ones .61 m long and gradually narrowing toward the tip. The leaves are also alternating, 3 m long, widely spreading apart or slightly ascending and slightly curved backward. The leaflets are descending, sublucid, and similarly green on both sides with scattered bristle-like spines on both surfaces.
Distribution: Caraga and Siquijor