Chrysopogon aciculatus is a perennial grass with culms 15–25 cm tall that ascend or grow erect from a decumbent base. The stems are stoloniferous, with extensively creeping stolons that are covered by imbricate, scale-like old sheaths and give rise to numerous sterile leafy shoots. The leaves are simple and alternate, with blades measuring 2–8 cm long and 3–5 mm wide, the uppermost often nearly obsolete. The blades are thin, glossy, and often undulate, with scabrous, sparsely serrate margins and sparsely papillose-hispid bases. Veins are parallel. Sheaths are 1–3 cm long, sometimes reaching 6 cm on upper leaves, striate and sometimes tinged purple, imbricate, and sparsely pilose at the throat and along the margins. Ligules are represented by a densely ciliate ridge about 0.2 mm long. Stipules are absent. The flowers are arranged in reddish-purple panicles that are narrowly elliptic and 3–6 cm long. Branches are slender, 0.5–1.5 cm long, whorled, and either stiffly ascending or appressed. Spikelet clusters are 6–8 mm long and disarticulate from the pedicel via a long, oblique, retrorsely barbed callus with a hispidulous ridge about 5 mm long. Sessile spikelets are 3–4 mm long, acute, glabrous, and scabrous along upper margins. The callus is pubescent, about 4 mm long, and oblique. The first glume is lanceolate, dorsally flattened, ca. 3.8 mm long, bifid, 2-nerved, scabrid-setose with revolute margins. The second glume is narrowly boat-shaped, about 3.4 mm long, 3-nerved, and has a short, scabrid-setose awn (~0.8 mm) at the midnerve tip; its margins are hyaline and pubescent. The first lemma is ~2.8 mm long, hyaline, with pubescent margins. The second lemma is 2.5–3 mm long and tapers into a ~5 mm awn. The palea is hyaline, oblong-acute, and ~1.6 mm long. Pedicellate spikelets are purple with pedicels 2–3 mm long, hispidulous at the apex. Glumes are ~5 mm long, scabrous at the apex, and acuminate or awn-pointed. The first floret is sterile, and the second is staminate; both lemmas are awnless and shorter than the glumes. The fruit is an oblong caryopsis approximately 2 mm long. It is found in dry, exposed areas, typically on slopes and ridges between 15-520 meters.