Glyceria maxima
Glyceria acutiflora
English watergrass, giant mannagrass, glycerie aquatique, reed manna grass, rough mannagrass, tall glyceria, tall mannagrass
creeping mannagrass, sharp-scale manna grass
60-250 cm tall, 6-12 mm thick, erect.
30-100 cm tall, 3-6 mm thick, spongy, usually decumbent and rooting at the lower nodes.
scabridulous, keeled;
ligules 1.2-6 mm, rounded or with a central point, ligules of the lower leaves thick, stiff, and opaque, ligules of the upper leaves thinner and translucent;
blades 30-60 cm long, 6-20 mm wide, both surfaces smooth or adaxial surfaces scabridulous.
smooth, weakly keeled;
ligules 5-9 mm;
blades 10-15 cm long, 3-8 mm wide, abaxial surfaces smooth, adaxial surfaces of the midcauline leaves often papillose.
15-45 cm long, to 30 cm wide, open;
branches 8-20 cm, lax, strongly divergent or drooping at maturity, scabridulous, primary branches with 50+ spikelets;
pedicels 0.8-10 mm.
often racemes, sometimes panicles, 15-35 cm long, 1-2 cm wide, open at anthesis, bases often enclosed in the flag leaf sheaths at maturity;
branches 5.5-8 cm (absent in racemose plants), solitary or in pairs, appressed, most branches with 1-3 spikelets, the lower branches sometimes with more than 3;
pedicels 1.5-2.5 mm.
5-12 mm long, 2-3.5 mm wide, somewhat laterally compressed, oval in side view, with 4-10 florets.
20-45 mm long, 2.5-3 mm wide, cylindrical and terete except slightly laterally compressed at anthesis, rectangular in side view, with 5-12 florets.
unequal, usually the midvein of 1 or both reaching to the apices;
lower glumes 2-3 mm;
upper glumes 3-4 mm, longer than wide;
rachilla internodes 0.5-1 mm;
lemmas 3-4 mm, 7-veined, veins scabridulous, apices broadly acute to rounded, slightly prow-shaped;
paleas subequal to the lemmas, lengths more than 3 times widths, keels not winged, ciliate, tips not strongly incurved, curved to broadly notched between the keels;
anthers 3, (1)1.2-2 mm.
unequal, acute;
lower glumes 1.3-4.5 mm;
upper glumes 3-7 mm;
rachilla internodes 2-3 mm;
lemmas 6-8.5 mm, scabridulous, 7-veined, gradually tapering from near midlength to the narrowly acute (< 45°) or acuminate apices;
paleas 0.7-3 mm longer than the lemmas, keels winged, tips parallel, intercostal region truncate, often splitting, apices appearing bifid, with 0.4-1 mm teeth;
anthers 3, 1-2 mm.
1.5-2 mm.
about 3 mm.
= 60.
= 40.
Glyceria maxima
Glyceria acutiflora
Glyceria maxima is native to Eurasia. It grows in wet areas, including shallow water, at scattered locations in the flora region. It is an excellent fodder grass, and may have been planted deliberately at one time (Dore and McNeill 1980). At some sites, the species appears to be spreading, largely vegetatively. It is easily confused with large specimens of G. grandis, but differs in its firmer, more prow-tipped lemmas as well as its larger lemmas and usually larger anthers.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Glyceria acutiflora grows in wet soils and shallow water of the northeastern United States, extending from Michigan and Missouri to the Atlantic coast between southwestern Maine and Delaware. Its long paleas make G. acutiflora the most distinctive North American species of sect. Glyceria.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
BC
WA
Flora NW
Go Botany
PNW Herbaria
WildflowerSearch
iNaturalist
USDA Plants Database
MD Biodiversity
MI Flora
MO Plants
