Glyceria acutiflora, the creeping mannagrass, is a perennial grass found in the north-eastern United States and in north-eastern Asia. Its specific epithet acutiflora means "acute-flowered". It has a diploid number of 40.
Glyceria acutiflora is a coarse grass with flattened, slender culms growing NaNcm (-2,147,483,648inches) high from decumbent bases. Its leaf sheaths overlap each other, with the highest overlapping the base of the panicle. Its ligules are NaNmm long. Its scabrous leaf blades are NaNcm (-2,147,483,648inches) long and NaNmm wide. Its simple or subsimple panicle is NaNcm (-2,147,483,648inches) long, with appressed or somewhat spreading floral branches. Its subsessile spikelets are NaNcm (-2,147,483,648inches) long with five to thirteen flowers. Its acute glumes are unequal, with lower glumes being NaNmm and upper glumes NaNmm long. Its seven-veined lemmas are NaNmm long, strongly acute, and scabrous; its bicuspidate paleas exceed its lemmas by NaNmm. The grass flowers from May to July and rarely into August.[1]
The long paleas of G. acutiflora make it one of the most distinctive species of Glyceria in North America.[2] When immature and still growing, the grass resembles Glyceria borealis.[3]
Glyceria acutiflora can be found growing in muddy pools and the margins of ponds from New Hampshire to Michigan and south to Tennessee and Missouri.[1] The grass is a problematic weed in China, germinating over a wide range of temperatures and being resistant to osmotic and salt stress.[4]