Annual herb, tufted 8 cm - 1 m tall Leaves: often crowded at the base. Sheaths usually longer than internodes, rounded, hairy (hairs to 5 mm long and bumpy-based). Ligules 0.5 - 1.5 mm long, membranous. Blades upright, greenish or purplish, 3 - 30 cm long, 2 - 6 mm wide, linear with a truncate (cut straight across) to nearly heart-shaped base and pointed tip, flat, parallel-veined, stiff-hairy to sparsely soft-hairy, marginally fringed with hairs at the base. Inflorescence: a branched arrangement of spikelets (panicle), diffuse, 7 - 27 cm long, 4 - 24 cm wide, one-fourth to one-third as long as the plant, with spreading primary branches and appressed secondary branches. Secondary branches with one to four spikelets. Fruit: a caryopsis, indehiscent, enclosed within the persistent lemma and palea. Culm: upright to decumbent, unbranched to many-branched, 8 cm - 1 m long, about 1 mm wide, round in cross-section, softly hairy (hairs bumpy-based). Nodes sparsely to densely soft-hairy. Spikelets: pale green or slightly reddish, 1.5 - 2 mm long, about 0.5 mm wide, egg-shaped to ellipsoid. Glumes: unequal, herbaceous. Lower glumes 0.5 - 1 mm long, less than half as long as spikelets, truncate (cut straight across) to pointed at the apex, three- to four-veined. Upper glumes hooked over the upper florets, 1.5 - 2 mm long, seven-veined. Lemmas:: Lower lemmas similar to upper glumes, hooked over the upper florets, 1.5 - 2 mm long, seven- to nine-veined, keeled. Upper lemmas shiny, with rolled-up margins on the upper surface. Paleas:: Lower paleas absent. Upper paleas longitudinally lined. Florets:: Lower florets sterile. Upper florets bisexual, nearly black, about 1.5 mm long, under 0.5 mm wide, over half as wide as long, pointed at the apex, shiny, minutely bumpy at the apex, with many pale veins. Anthers three. Stigmas red.
Similar species: No information at this time.
Habitat and ecology: No information at this time.
Occurence in the Chicago region: native
Etymology: Panicum comes from the Latin word panis, meaning bread, or panus, meaning "ear of millet." Philadelphicum means "of or from Philadelphia."