Habit: Cenchrus gracillimus grows as a decumbent annual to 50 centimeters in length. The leaves are arranged alternately with a sheath extending along the stem that is pubescent along its edge. At the point of divergence of the leaf sheath to the leaf blade is a ciliate ligule. The leaves are parallel veined and to 7 centimeters in length and less than 3 mm wide at the point of divergence.
The imperfect, incomplete, zygomorphic flowers are arranged in a terminal racemose panicle. The flowers are highly modified without identifiable structures such as the calyx or corolla. Each flowering unit is a spikelet at the base of which are 2 yellow brown structures called glumes. In the spikelet, there are 2 flowering structures each is subtended by 2 additional structures (lemma and palea). The entire spikelet surrounded by bracts that are sharpened into spines forming a burr. There is space between the burrs in which the rachis is visible. In each flower within the spikelet there are 3 stamens. The fruit is a caryopsis that turns black at maturity. The entire spikelet/burr is the dispersal unit.
Cenchrus gracillimus differs from C. gracillimus in the lack of of the smaller bristles on the burr and narrower leaf blade. Cenchrus gracillimus differs from C. incertus in the size of the burrs (smaller) and the leaf length and wide (narrower).
Habitat: Cenchrus gracillimus grows in sandy areas that are Human Altered environments (lawns, abandoned fields, disturbed areas).
Distribution: Cenchrus gracillimus occurs throughout the island groupings within the Lucayan Archipelago as well as the Greater Antilles and the southern United States.
Medicinal/Cultural/Economic usage: Cenchrus gracillimus has not been used medicinally in the Lucayan Archipelago.