Glyceria septentrionalis
Glyceria septentrionalis var. septentrionalis
eastern manna grass, floating manna grass, glycerie septentrionale, northern glyceria, northern mannagrass
73-182 cm tall, to 8 mm thick, often decumbent and rooting from 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.
(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.
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.
1.5-2 mm;
hila about as long as the caryopses.
5-10 mm;
blades 2-15 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.
branches 3-17 cm, with 1-9 spikelets.
internodes 1.1-1.8 mm.
scabrous over the veins, prickles about 0.05 mm, scabrous or scabridulous between the veins, apices almost truncate to obtuse or acute, apical margins crenate to entire.
= 40.
Glyceria septentrionalis
Glyceria septentrionalis var. septentrionalis
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 septentrionalis var. septentrionalis grows throughout the range of the species, but is less common in the lower floodplain of the Mississippi River and Kentucky than var. arkansana. It is found in shallow water or wet soils. In reviewing specimens for this treatment, some were found to have acute lemmas that usually exceeded the paleas, and lemma midveins that were clearly longer than the other veins; others had truncate to obtuse lemmas that were usually shorter than or equaling the paleas, and lemma midveins that were barely longer than the lateral veins. Further study is needed to determine whether the two kinds merit separate recognition.
(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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