Plants rhizomatous, rhizomes relatively long and slender. Panicles terminal and axillary; branches more numerous, appressed, congested, with dense clusters of spikelets. Spikelets 2.3-2.8 mm, not clearly falcate, often ovoid-lanceolate, purplish-stained, acute.
Panicum anceps subsp. rhizomatum grows in the Atlantic and Gulf coastal plains.
The small, crowded, often purplish spikelets of this subspecies often closely resemble those of Panicum rigidulum.