Glyceria septentrionalis
Glyceria elata
eastern manna grass, floating manna grass, glycerie septentrionale, northern glyceria, northern mannagrass
fowl manna grass, tall mannagrass
73-182 cm tall, to 8 mm thick, often decumbent and rooting from the lower nodes.
75-150 cm tall, 2.5-8 mm thick, spongy, decumbent and rooting at the lower nodes.
smooth or scabridulous, keeled;
ligules 5-16 mm;
blades 18-32 cm long, 2-15 mm wide, abaxial surfaces scabrous, adaxial surfaces scabridulous, usually glabrous, midcauline leaves sometimes papillose.
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.
15-60 cm long, 1-3.5 cm wide;
branches 3-17 cm, usually erect to strongly ascending, sometimes spreading at anthesis, usually straight, sometimes lax, with 1-9 spikelets;
pedicels 0.7-1.7 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.
(6.5)10-23 mm long, 1-3 mm wide, cylindrical and terete, except at anthesis when slightly laterally compressed, rectangular in side view, with 8-16 florets.
3-6 mm long, 1.5-2.8 mm wide, laterally compressed, oval in side view, with 3-4(6) florets.
elliptic to obovate, apices rounded to acute;
lower glumes (0.3)1.5-3.7 mm;
upper glumes (1.9)2.3-5.2 mm;
rachilla internodes 1.1-1.8 mm;
lemmas 2.4-4.8 mm, veins scabrous or hispidulous, intercostal regions scabridulous, scabrous, or hispidulous, midveins extending to within 0.1 mm of the apical margins, apices truncate to obtuse or acute, apical margins crenate to entire;
paleas from slightly shorter than to exceeding the lemmas, apices bifid, teeth to 0.2 mm;
anthers 3, 0.5-1.8 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.
1.5-2 mm;
hila about as long as the caryopses.
0.8-1.5 mm long, 0.5-0.7 mm wide;
hila as long as the caryopses.
= 20.
Glyceria septentrionalis
Glyceria elata
Glyceria septentrionalis is native and restricted to North America. It grows in shallow water or very wet soils, from southern Quebec to the east coast and south to eastern Texas and South Carolina. Voss (1972) stated that it is the floating leaves of G. septentrionalis that develop papillose, non-wettable adaxial surfaces. They seem to be developed less often than in G. borealis; whether this reflects a difference in habitat or growth habit is not known.
Glyceria septentrionalis resembles G. notata in its rather short, truncate to rounded lemmas, but it tends to have fewer spikelets on its branches. In addition, the veins of its leaf sheaths appear completely smooth, even under high magnification. That said, many specimens will be hard to identify if their provenance is not known.
(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.)
1. Lemmas hispidulous over the veins, hairs about 0.1 mm long | var. arkansana |
1. Lemmas scabrous over the veins, prickles about 0.05 mm long | var. septentrionalis |
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