Glyceria obtusa
Glyceria elata
Atlantic manna grass
fowl manna grass, tall mannagrass
60-100 cm tall, 2.5-5 mm thick, often decumbent at the base.
75-150 cm tall, 2.5-8 mm thick, spongy, decumbent and rooting at the lower nodes.
glabrous, smooth, not keeled, midvein prominent;
ligules 0.5-0.8 mm, not translucent, truncate to slightly rounded;
blades 15-40 cm long, 2-8 mm wide, abaxial surfaces smooth, 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.
5-15 cm long, 2.5-6 cm wide, ovoid, erect, dense;
branches 2.5- 8 cm, strongly ascending, with 10-30 spikelets;
pedicels 1-14 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.
4-7 mm long, 2.5-4 mm wide, somewhat laterally compressed, oval in side view, with 4-7 florets.
3-6 mm long, 1.5-2.8 mm wide, laterally compressed, oval in side view, with 3-4(6) florets.
keeled, 1-veined, veins not extending to the apical margins, apical margins hyaline, acute, entire or often splitting with age;
lower glumes 1.6-2.5 mm, lanceolate to narrowly ovate or obovate;
upper glumes 1.7-3.5 mm, ovate-elliptic to obovate, obtuse to rounded;
rachilla internodes 0.2-0.4 mm;
lemmas 3-3.9 mm, 5-9-veined, veins not raised, apices rounded, somewhat prow-shaped;
paleas subequal to the lemmas, lengths 2-2.8 times widths, keels well-developed, not winged, tips pointing towards each other, narrowly notched between the keels;
anthers 2, 0.6-0.8 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.
1.5-1.8 mm.
0.8-1.5 mm long, 0.5-0.7 mm wide;
hila as long as the caryopses.
= 40.
= 20.
Glyceria obtusa
Glyceria elata
Glyceria obtusa is a distinctive species that grows in wet woods, swamps, and shallow waters, primarily on the eastern seaboard of North America, from Nova Scotia and New Brunswick to South Carolina.
(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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