Panicum fauriei var. carteri is a cespitose annual grass growing 2 to 30 cm tall, sometimes reaching up to 46 cm. Its culms are usually branched and puberulent, with puberulent or short-pilose nodes. The leaves are alternate and cauline, with blades ranging from 1.5 to 12 cm in length and 0.1 to 0.4 cm in width, often loosely involute, featuring pilose upper surfaces and puberulent lower surfaces. The sheaths are typically puberulent, with auricular hairs that are usually prominent, measuring 1 to 2.5 mm in length, and a ligule that is a ciliate membrane, 0.4 to 1.6 mm long. It produces 1 to 11 cm long panicles, with puberulent or sparsely pilose axes and branches that are usually appressed and puberulent or pilose. Its spikelets (pictured) are 1.8 to 2.3 mm long, acute, and short pubescent, with the first glume as long as the spikelet. It has a sterile first floret and a second floret that is dark brown at maturity, smooth, and glossy, measuring 1.2 to 1.8 mm in length and 0.5 to 0.7 mm in width, with anthers 0.8 to 1.1 mm long. The fruit is a caryopsis. It typically grows in dry, open, often rocky habitats, including lava flows, rocky shores, raised coralline reefs, and dunes between 0-400 meters.