Northern Prairie Wildlife Research Center
Aquatic and Wetland Vascular Plants of the Northern Great Plains
63. Poaceae, the Grass Family
13. Glyceria R. Br. -- Mannagrass
1. Glyceria borealis (Nash) Batch. -- Northern mannagrass
Culms 5-13 dm tall, rather weak, sometimes decumbent at the base, often
producing adventitious roots from submersed lower nodes. Leaf blades
2-6 mm wide, glabrous; sheaths glabrous, the ligule scarious, rounded,
3-10 mm long. Panicle 15-40 cm long, with stiff, erect to ascending,
racemelike branches. Spikelets linear, mostly 6- to 13-flowered, 9-15
mm long; glumes obtuse, the first 1.5-2 mm long, the second 2.5-3.5 mm
long; lemmas oblanceolate, 3-4 mm long, obtuse to subacute, scarious-margined,
scaberulous on the nerves; anthers 3, 0.5-0.9 mm long. Grain dark
brown, oblong to ovoid, apiculate at the base, furrowed on the upper face, 1.5
mm long. Jun--Aug. In shallow water or mud of streams, ditches, ponds and marshes;
frequent in ND and ne SD, otherwise rare in w SD and n NE; (Newf. to AK, s to
NJ, PA, IL, MN, SD, NM, AZ and CA).
Glyceria fluitans (L.) R. Br. is a similar species found only in
the Black Hills; otherwise it occurs well east of the region. It differs from
G. borealis in the longer, more scabrous lemmas 4-7 mm long.
This species is known from Custer and Pennington Counties, SD.
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