Vascular Plants of North Carolina
Account for Floating Mannagrass - Glyceria septentrionalis   A.S. Hitchcock
Members of Poaceae:
Members of Glyceria with account distribution info or public map:
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Section 5 » Order Cyperales » Family Poaceae
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AuthorA.S. Hitchcock
DistributionMostly the Piedmont and northern Coastal Plain; scarce in the southern Coastal Plain and the Mountains.

MA to MN south to GA and TX.
AbundanceUncommon throughout, except rare in the southern Coastal Plain and the Mountains. Can be fairly common in the northern Coastal Plain.
HabitatFresh marshes, depressions in floodplain forests, wet meadows, and clearings on floodplains.
PhenologyFlowering and fruiting May-June. Spikelets fall soon after ripening.
IdentificationThis species belongs to the group of mannagrasses with long, slender spikelets. The elongate spikelets are strongly ascending or even erect along the inflorescence stalk. The alien G. declinata has been collected in Alleghany and Watauga Counties; its leaves are shorter (3-12 cm long vs. 18-32 cm long).
Taxonomic CommentsOur plants are var. septentrionalis, though Weakley (2018) does not recognize varieties.

Glyceria is a genus with 2 groups of species. One has linear, elongate spikelets that are often appressed to the inflorescence stalks. The second has short, generally ovoid spikelets that are in a very open and branched inflorescence; note that in this group, G. melicaria and G. obtusa spikelets are rather appressed and the inflorescence is narrow to cylindrical. In all species the lemmas have prominent, raised ribs. In general, Glyceria species grow in wet soils.
Other Common Name(s)Eastern Mannagrass, Northern Mannagrass
State RankS3 [S3S4]
Global RankG5
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US Status
USACE-agcpOBL link
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B.A. SorrieSame data. MoorePhoto_natural
B.A. SorrieTriassic Basin, meadow by McLendon's Creek, Kelly Plantation Road, late May 2015. MoorePhoto_natural
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