Common Name: blue panicum

Duration: Perennial

Nativity: Non-Native

Lifeform: Graminoid

General: Stout tufted perennial grass, 0.5- 3 m tall, from knotted, pubescent rhizomes with scalelike leaves, the rhizomes to 1 cm thick; stems erect to ascending, 2-4 mm thick, compressed, hard, becoming almost woody; nodes swollen; nodes and internodes glabrous.

Vegetative: Sheaths not keeled, shorter than or equal to internodes, lower sheaths partially pubescent; blades 10-60 cm long, 3-20 mm wide, elongate, flat with lower surfaces and margins scabrous, upper surfaces occasionally pubescent near the base; ligules 0.5-1.5 m

Inflorescence: Open to contracted panicle, 10-45 cm long, half as wide as long; branches 4-12 cm, ascending to spreading; spikelets 3 mm long, narrowly ovoid, often purplish, short pediceled, densely clustered on branchlets, 2-flowered, the first floret staminate and the second floret bisexual; lower glume one third to half as long as spikelets, 3-5 veined; upper glume subequal to lower glume, glabrous, 5-9 veined; fertile lemma indurate, 2-3 mm long, smooth, lustrous, acute.

Ecology: Found in open disturbed areas and along fields, below 5,000 ft (1524 m); flowers April to October.

Distribution: Native to w Asia, from the Arabian Peninsula to the Indian Subcontinent; naturalized in the sw US, from CA to TX; south to MEX; also S. Amer., Hawaii, and Australia.

Notes: The genus Panicum is defined as having unawned spikelets with 2 florets, the first floret sterile or staminate, and the second floret bisexual with a rigid lemma that clasps the palea. P. antidotale is a rhizomatous perennial grass with stout, almost reedlike stems that have obviously swollen nodes; blue-green herbage, and a densely flowered, often reddish panicle. Hopia obtusa is another stout, rhizomatous Panicum-like grass; however, that species has a narrow, contracted panicle. Panicum bulbosum (syn. Zuloagaea bulbosa), another rhizomatous perennial, has a more sparsely flowered panicle, is usually a smaller plant, and has hard, rounded, corm-like swellings at the base of the stems. P. antidotale was introduced from India by the soil conservation corps, and has now become naturalized.

Ethnobotany: In India the plant was burned and the smoke used to disinfect smallpox wounds.

Etymology: Panicum is a classical Latin name for millet, while antidotale is derived from the same root as antidote, probably referring to its use as a smallpox treatment.

Synonyms: Panicum kermesinum, Panicum longijubatum, Panicum miliare, Panicum proliferum, Panicum subalbidum

Editor: SBuckley 2010, AHazelton 2015