Poaceae

American mannagrass

Glyceria grandis S.Watson

Family: Poaceae
Genus: Glyceria

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American mannagrass: Glyceria grandis can aggressively colonize roadside ditches and irrigation canals possibly even competing with Phalaris arundinacea with which it often co-exist — Photo: Matt Lavin from Bozeman, Montana, USA, CC BY-SA 2.0, from Wikimedia Commons

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Common names

By language (3)

English: American mannagrass, Reed manna grass
Finnish: Lännenisosorsimo, Lännensorsimo
Swedish: Kvarngröe

Synonyms

Glyceria americana (Torr.) Pammel
Glyceria arundinacea subsp. grandis (S.Watson) Tzvelev
Glyceria flavescens M.E.Jones
Glyceria grandis f. grandis
Glyceria grandis f. pallescens Fernald
Glyceria grandis var. grandis
Glyceria grandis var. komarovii Kelso
Glyceria hulteniana Á.Löve
Glyceria maxima f. pallescens (Fernald) B.Boivin
Glyceria maxima subsp. grandis (S.Watson) Hultén
Glyceria maxima var. americana (Torr.) B.Boivin
Glyceria maxima var. grandis (S.Watson) Breitung
Panicularia americana (Torr.) MacMill.
Panicularia grandis (S.Watson) Nash
Poa aquatica var. americana Torr.

Characteristics

Growth habit: Graminoid
Lifespan: Perennial
In the US and Canada: Alaska: native, Canada: native, Lower 48 states: native, St. Pierre and Miquelon: native

Photos

Photo: Matt Lavin from Bozeman, Montana, USA, CC BY-SA 2.0, from Wikimedia Commons
Photo: Matt Lavin from Bozeman, Montana, USA, CC BY-SA 2.0, from Wikimedia Commons
Photo: Matt Lavin from Bozeman, Montana, USA, CC BY-SA 2.0, from Wikimedia Commons
Photo: Matt Lavin from Bozeman, Montana, USA, CC BY-SA 2.0, from Wikimedia Commons
Photo: Matt Lavin from Bozeman, Montana, USA, CC BY-SA 2.0, from Wikimedia Commons
Photo: Matt Lavin from Bozeman, Montana, USA, CC BY-SA 2.0, from Wikimedia Commons
Photo: Matt Lavin from Bozeman, Montana, USA, CC BY-SA 2.0, from Wikimedia Commons
Photo: Matt Lavin from Bozeman, Montana, USA, CC BY-SA 2.0, from Wikimedia Commons
Photo: Matt Lavin from Bozeman, Montana, USA, CC BY-SA 2.0, from Wikimedia Commons
Photo: Matt Lavin, CC BY-SA 2.0, from Wikimedia Commons
Photo: Matt Lavin, CC BY-SA 2.0, from Wikimedia Commons
Photo: Matt Lavin, CC BY-SA 2.0, from Wikimedia Commons

More in Glyceria

Sources: classification, synonyms from World Flora Online Plant List (2026-06, CC0 1.0); common names, popularity from Wikidata (2026-10-26, CC0 1.0); common names, US characteristics from USDA PLANTS Database (2025-05-29, CC0 1.0). About our plant data.