Glyceria septentrionalis
Glyceria grandis
eastern manna grass, floating manna grass, glycerie septentrionale, northern glyceria, northern mannagrass
American glyceria, American manna grass, manna grass, reed mannagrass, tall mannagrass
73-182 cm tall, to 8 mm thick, often decumbent and rooting from the lower nodes.
50-150 (200) cm tall, 8-12 mm thick, erect or decumbent and rooting at the base.
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.
smooth or scabridulous, keeled;
ligules 1-5 (7) mm, truncate to rounded, ligules of the lower leaves stiff at the base, ligules of the upper leaves flexible throughout;
blades 25-43 cm long, 4.5-15 mm wide.
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.
16-42 cm long, 12-20 cm wide, open;
branches (7)10-18 cm, lax, widely divergent to drooping, with 35-80+ spikelets;
pedicels 1-15 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.
3.2-10 mm long, 2-3 mm wide, somewhat laterally compressed, oval to elliptic in side view, with 4-10 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.
mostly hyaline, usually the midvein of 1 or both glumes extending to the apices, apices acute;
lower glumes 1-2.3 mm;
upper glumes 1.5-2.7 mm;
rachilla internodes 0.5-0.8 mm;
lemmas 1.8-3 mm, prominently (5)7-veined, veins often scabridulous, intercostal regions smooth, apices rounded to truncate, sometimes erose, almost flat at maturity;
paleas from shorter than to slightly longer than the lemmas, lengths more than 3 times widths, keels not winged, ciliolate, tips not strongly incurved, truncate to notched between the keels;
anthers 3, 0.5-1.2 mm.
1.5-2 mm;
hila about as long as the caryopses.
1-1.5 mm.
=20.
Glyceria septentrionalis
Glyceria grandis
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 grandis grows on banks and in the water of streams, ditches, ponds, and wet meadows, from Alaska to Newfoundland and south in the mountains to California, Arizona, and New Mexico in the western United States, and to Virginia and Tennessee in the eastern United States. It is similar to G. maxima, differing primarily in its shorter, flatter lemmas and shorter anthers. It is also confused with G. elata and Torreyochloa pallida. It differs from the former in having acute glumes with long veins, more evenly dark florets, flatter lemma apices, and paleal keel tips that do not point towards each other. It differs from Torreyochloa pallida in its closed leaf sheaths and 1-veined glumes.
(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 |
1. Spikelets 3.2-6.4 mm long, with 4-8 florets | var. grandis |
1. Spikelets 6-10 mm long, with 5-10 florets | var. komarovii |
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