Glyceria maxima
Glyceria elata
English watergrass, giant mannagrass, glycerie aquatique, reed manna grass, rough mannagrass, tall glyceria, tall mannagrass
fowl manna grass, tall mannagrass
60-250 cm tall, 6-12 mm thick, erect.
75-150 cm tall, 2.5-8 mm thick, spongy, 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.
scabridulous or hirtellous, not or weakly keeled;
ligules 2.5-4(6) mm, truncate to acute, erose, puberulent;
blades 19-40+ mm long, 6-12(15) mm wide, abaxial surfaces smooth or scabridulous, adaxial surfaces usually scabrous, sometimes scabridulous.
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.
15-30 cm long, 12-30 cm wide, pyramidal, open;
branches 12-17 cm, divergent to drooping, lax, with 30-50+ spikelets;
pedicels 0.3-5 mm.
5-12 mm long, 2-3.5 mm wide, somewhat laterally compressed, oval in side view, with 4-10 florets.
3-6 mm long, 1.5-2.8 mm wide, laterally compressed, oval in side view, with 3-4(6) 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.
1-1.5(2) times longer than wide, narrowing beyond midlength, veins terminating below the apical margins, apices obtuse to rounded;
lower glumes 0.7-1.5 mm;
upper glumes 1-1.5 mm;
rachilla internodes 0.5-0.6 mm;
lemmas 1.7-2.2 mm, oval in dorsal view, 5-7-veined, veins raised throughout, scabridulous, apices rounded, prow-shaped;
paleas subequal to or often slightly longer than the lemmas, lengths 2.4-3 times widths, oval in dorsal view, keels not winged, tips pointing towards each other, apices narrowly notched between the keels;
anthers 2, 0.5-0.8 mm.
1.5-2 mm.
0.8-1.5 mm long, 0.5-0.7 mm wide;
hila as long as the caryopses.
= 60.
= 20.
Glyceria maxima
Glyceria elata
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 elata grows in wet meadows and shady moist woods, from British Columbia east to Alberta and south to California and New Mexico. It is not known from Mexico. The anomalous record from Georgia may represent an inadvertent introduction. It is very similar to, and sometimes confused with, G. striata, but the two sometimes grow together and show no evidence of hybridization. Their differences in growth habit and stature are evident in the field. Molecular data (Whipple et al. [in press]) confirm that G. elata and G. striata are distinct, closely related entities.
Glyceria elata is also sometimes confused with G. grandis. It differs in having rounded glumes with veins that terminate below the apices, more readily disarticulating florets, and greener lemmas with more prow-shaped apices, as well as in having paleal keel tips that point towards each other. In its overall aspect, it also resembles G. pulchella, but has somewhat more lax panicle branches than that species, in addition to smaller spikelets and florets.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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