Glyceria septentrionalis
Glyceria nubigena
eastern manna grass, floating manna grass, glycerie septentrionale, northern glyceria, northern mannagrass
great Smoky Mountain glyceria, great Smoky Mountain mannagrass
73-182 cm tall, to 8 mm thick, often decumbent and rooting from the lower nodes.
100-200 cm tall, 3-5 mm thick, smooth.
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, weakly keeled;
ligules 1-1.5 mm, truncate;
blades to 45 cm long, 6-10 mm wide, abaxial surfaces smooth or scabrous, adaxial surfaces scabrous.
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.
20-30 cm long, 7.5-14 cm wide, open, pyramidal;
branches 7.5-14 cm, spreading or reflexed, lax, with 16-80 spikelets;
pedicels 2-7 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.
3.5-5.5 mm long, 2-3(3.5) mm wide, laterally compressed, oval in side view, with 3-5 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.
tapering from below midlength to the narrowly (< 45°) acute apices, veins not extending to the apices;
lower glumes 0.8-1.5 mm;
upper glumes 1.8-2.2 mm;
rachilla internodes about 0.5 mm;
lemmas 2.2-2.7 mm, 0.9-1.1 mm wide in dorsal view, veins distinctly raised, usually smooth over and between the veins, sometimes scabridulous over the veins, apices acute, prow-shaped;
paleas slightly shorter than the lemmas, lengths 2-2.7 times widths, keels not winged, tips incurved, apices narrowly notched between the keels;
anthers 2, about 1.5 mm, dehiscent at maturity.
1.5-2 mm;
hila about as long as the caryopses.
about 1.5 mm.
= 40.
Glyceria septentrionalis
Glyceria nubigena
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 nubigena is known only from moist areas of balds and high ridges in the Great Smoky Mountains of North Carolina and Tennessee.
(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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