Glyceria obtusa

(Muhl.) Trin.
Common names: Atlantic mannagrass
Endemic
Treatment appears in FNA Volume 24. Treatment on page 75.
Please click on the illustration for a higher resolution version.
Illustrator: Cindy Roché

Copyright: Utah State University

Plants perennial. Culms 60-100 cm tall, 2.5-5 mm thick, often decumbent at the base. Sheaths 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. Panicles 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. Spikelets 4-7 mm long, 2.5-4 mm wide, somewhat laterally compressed, oval in side view, with 4-7 florets. Glumes 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. Caryopses 1.5-1.8 mm. 2n = 40.

Distribution

Maine, Md., N.J., Mass., N.Y., N.H., Del., D.C., N.C., S.C., Va., Pa., Conn., R.I., N.B., N.S.

Discussion

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.

Selected References

None.

Lower Taxa

None.

"decumbent" is not a number.

... more about "Glyceria obtusa"
membranous +  and scarious +
0.06 cm0.6 mm <br />6.0e-4 m <br /> (0.08 cm0.8 mm <br />8.0e-4 m <br />) +
entire +  and truncate +
prow--shaped +  and rounded +
Mary E. Barkworth +  and Laurel K. Anderton +
(Muhl.) Trin. +
1 (?) +  and 3 (?) +
basal +  and apical +
keeled +  and rounded +
pseudopetiolate +  and branching +
persistent +
intravaginal +, extravaginal +, branching +  and basal +
swelling +
15 cm150 mm <br />0.15 m <br /> (40 cm400 mm <br />0.4 m <br />) +
folded +  and flat +
0.2 cm2 mm <br />0.002 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
2.5 cm25 mm <br />0.025 m <br /> (8 cm80 mm <br />0.08 m <br />) +
Atlantic mannagrass +
not cormous +  and rooting +
60 cm600 mm <br />0.6 m <br /> (100 cm1,000 mm <br />1 m <br />) +
decumbent +  and erect +
20 cm200 mm <br />0.2 m <br /> (250 cm2,500 mm <br />2.5 m <br />) +
not woody +
0.25 cm2.5 mm <br />0.0025 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
Maine +, Md. +, N.J. +, Mass. +, N.Y. +, N.H. +, Del. +, D.C. +, N.C. +, S.C. +, Va. +, Pa. +, Conn. +, R.I. +, N.B. +  and N.S. +
0 +  and 1/3 +
liquid +, soft +  and hard +
capillary +
sometimes longer +
4 +  and 7 +
compressed +
reduced +
shorter than to longer than the adjacent lemmas +
subtending +
much smaller +
scarious +  and membranous +
5-11-veined +
uncinate +
hairy +, glabrous +, scabrous +  and smooth +
prow--shaped +
0.3 cm3 mm <br />0.003 m <br /> (0.39 cm3.9 mm <br />0.0039 m <br />) +
membranous +  and thinly coriaceous +
truncate +  and slightly rounded +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.08 cm0.8 mm <br />8.0e-4 m <br />) +
inconspicuous +
lanceolate +
lanceolate +  and narrowly ovate or obovate +
0.16 cm1.6 mm <br />0.0016 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
concealed +  and prominent +
2 +  and 1 +
well-developed +
slightly longer +
subequal +
5cm +  and 15cm +
2.5 cm25 mm <br />0.025 m <br /> (6 cm60 mm <br />0.06 m <br />) +
0.1 cm1 mm <br />0.001 m <br /> (1.4 cm14 mm <br />0.014 m <br />) +
dry +  and fleshy +
not keeled +
0.4 cm4 mm <br />0.004 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
10 +  and 30 +
oval +  and compressed +
0.25 cm2.5 mm <br />0.0025 m <br /> (6 cm60 mm <br />0.06 m <br />) +
2.5mm +  and 4mm +
1 +  and 3 +
simple +  and compound +
2 (?) +  and 3 (?) +
Gramineae +
Glyceria obtusa +
Glyceria sect. Striatae +
species +
notched +
membranous +
ovate-elliptic +  and obovate obtuse +
0.17 cm1.7 mm <br />0.0017 m <br /> (0.35 cm3.5 mm <br />0.0035 m <br />) +
not raised +
aquatic +  and terrestrial +