Panicum hirticaule

Plants annual; glabrous or hispid, hairs papillose-based. Culms 11-110 cm, erect to decumbent; nodes shortly hirsute or glabrous. Sheaths shorter than the internodes, greenish to purplish, glabrous or with papillose-based hairs, ciliate on 1 margin, glabrous on the other; collars hirsute; ligules 1.5-3.5 mm, of hairs; blades 3-30 cm long, 3-30 mm wide, flat, usually hirsute or sparsely pubescent, hairs papillose-based, sometimes glabrous, bases rounded to cordate-clasping, margins ciliate, cilia papillose-based, apices acute. Panicles 9-30 cm long, 5-8 cm wide, erect or nodding, partially included to well-exserted, rachises glabrous or sparsely hispid basally; primary branches usually alternate to opposite, divergent, secondary branches and pedicels confined to the distal 2/3; pulvini inconspicuous; secondary branches appressed; pedicels 9-27 mm, appressed. Spikelets 1.9-4 mm long, 0.8-1 mm wide, ovoid to almost spherical, often reddish-brown, glabrous, veins prominent, scabridulous, apices abruptly acuminate. Lower glumes 1.3-2.4 mm, 1/2 - 3/4 as long as the spikelets, 3-5-veined; upper glumes 1.8-3.3 mm, 7-11-veined; lower florets sterile; lower lemmas similar to the upper glumes, 9-veined; lower paleas 0.4-0.9 mm; upper florets 1.5-2.4 mm long, 0.4-0.8 mm wide, ellipsoid, smooth or conspicuously papillate, shiny, stramineous, often with a lunate scar at the base.

Distribution

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Okla., N.Mex., Tex., Nev., Calif., Wash., Ariz.

Discussion

Panicum hirticaule grows in rocky or sandy soils in waste places, roadsides, ravines, and wet meadows along streams. Its range extends from southeastern California and southwestern Texas southward through Mexico, Central America, Cuba, and Hispaniola to western South America and Argentina.

Selected References

None.

Lower Taxa

Panicum hirticaule subsp. hirticaule, Panicum hirticaule subsp. sonorum, Panicum hirticaule subsp. stramineum

Key

1	Blades rounded at the base, 3-16 mm wide; lower paleas less than 1/2 as long as the upper florets; panicles erect	Panicum hirticaule subsp. hirticaule
1	Blades cordate, clasping at the base, 4-30 mm wide; lower paleas more than 1/2 as long as the upper florets; panicles often nodding.	> 2
2	Nodes, sheaths, and blades glabrous or sparsely pilose, hairs papillose-based; culms usually less than 70 cm tall; spikelets 3.2-4 mm long	Panicum hirticaule subsp. stramineum
2	Nodes, sheaths, and blades hirsute, hairs papillose-based; culms robust, usually more than 70 cm tall; spikelets 3-3.3 mm long	Panicum hirticaule subsp. sonorum