Andropogon glomeratus

Plants cespitose, upper portion dense, oblong to oblanceolate or obpyramidal. Culms 20-250 cm; internodes green, sometimes glaucous; branches mostly erect, straight. Sheaths usually scabrous, sometimes smooth; ligules 0.6-2.2 mm, sometimes ciliate, cilia to 0.9 mm; blades 13-109 cm long, 2.9-9.5 mm wide, glabrous or sparsely to densely pubescent, hairs usually spreading, rarely appressed. Inflorescence units 10-600 per culm; subtending sheaths (2.0)2.9-4.4(6.5) cm long, (1.5)2.3-3.4(4.4) mm wide; peduncles (1)6-14(60) mm, with 2(4) rames; rames (1)1.7-2.5(3.5) cm, exserted or not at maturity, pubescence sparse basally and increasing in density distally within each internode. Sessile spikelets 3-5 mm; callus hairs 1-2.5 mm; keels of lower glumes sometimes scabrous below midlength, usually scabrous distally; awns 6-19 mm; anthers 1(3), 0.5-1.5 mm, yellow, red, or purple. Pedicellate spikelets vestigial or absent, sterile. 2n = 20.

Distribution

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Del., D.C, W.Va., Pacific Islands (Hawaii), N.C., N.Y., R.I., S.C., Utah, Fla., Okla., Tex., N.J., Ark., Ariz., Calif., Ga., La., Md., Miss., N.Mex., Nev., Puerto Rico, Va., Virgin Islands, Tenn., Pa., Ala., Ill., Mass., Ohio, Ky.

Discussion

Andropogon glomeratus hybridizes with both A. longiberbis and A. virginicus. Some of its varieties are morphologically similar to the latter species.

Selected References

None.

Lower Taxa

Andropogon glomeratus var. glaucopsis, Andropogon glomeratus var. glomeratus, Andropogon glomeratus var. hirsutior, Andropogon glomeratus var. pumilus, Andropogon glomeratus var. scabriglumis

Key

1	Blades glaucous, glabrous, and smooth	Andropogon glomeratus var. glaucopsis
1	Blades green, often pubescent or scabrous	> 2
2	Sheaths subtending the inflorescence units 1.5-3 mm wide; leaf sheaths usually smooth; ligules ciliate, the cilia 0.2-0.9 mm long	Andropogon glomeratus var. pumilus
2	Sheaths subtending the inflorescence units (1.5)2.3-3.4(4.4) mm wide; leaf sheaths often scabrous; ligules, when ciliate, with the cilia no more than 0.5 mm long.	> 3
3	Keels of the lower glumes scabrous below and beyond midlength	Andropogon glomeratus var. scabriglumis
3	Keels of the lower glumes usually smooth below midlength, scabrous distally.	> 4
4	Upper portion of the plants oblong to obpyramidal; mature peduncles (4)11-35(60) mm long; anthers eventually falling	Andropogon glomeratus var. glomeratus
4	Upper portion of the plants cylindrical to oblong; mature peduncles 2-5 (8) mm long; withered remnants of anthers retained within the spikelets	Andropogon glomeratus var. hirsutior