BugwoodWiki Article

rough mannagrass
Glyceria maxima (Hartman) Holmb.

Overview

Appearance
Glyceria maxima is a perennial, semi-aquatic, rhizomatous grass. Stems are unbranched and can reach 2-8.2 ft. (0.6-2.5 m) in height.
Foliage
Leaves are 12-23.6 in. (30-60 cm) long, 0.2-0.8 in. (6-20 mm) wide, with an acute apex and a prominent midrib. The leaf margins have stiff, short hairs. The leaf sheaths are rough in texture with a reddish-brown band at the leaf junction.
Flowers
Flowering occurs from June through August, when flowers appear in 6-12 in. (15-30 cm) long open panicles. The panicle branches have short, stiff hairs like those on the leaf margins.
Fruit
The small seeds are 0.06-0.08 in. (1.5-2 mm) long, obovoid in shape and smooth in texture. This plant reproduces primarily vegetatively through rhizomes.
Ecological Threat
Glyceria maxima occurs in sunny to semi-shady wetlands, where it can form dense impenetrable monocultures that crowd out native species. It is native to northern Eurasia and was first found in North America in 1940 on the edge of Lake Ontario.

Resources

Selected Images


5272011
5272011

rough mannagrass
Glyceria maxima
Flower(s)
Leslie J. Mehrhoff
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5450212

rough mannagrass
Glyceria maxima
Feature(s)
Leslie J. Mehrhoff
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5450226

rough mannagrass
Glyceria maxima
Feature(s)
Leslie J. Mehrhoff
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5450227

rough mannagrass
Glyceria maxima
Feature(s)
Leslie J. Mehrhoff

Maps


EDDMapS Distribution - This map is incomplete and is based only on current site and county level reports made by experts, herbaria, and literature. For more information, visit www.eddmaps.org

EDDMapS Distribution

State Regulated List - This map identifies those states that list this species on their regulated list. For more information, visit Invasive.org

State Regulated List

Taxonomic Rank

Kingdom: Plantae
Phylum: Magnoliophyta
Class: Liliopsida
Subclass: Commelinidae
Order: Cyperales
Family: Poaceae
Genus: Glyceria

Other System Links

Plants: GLMA3
GRIN: 17680
ITIS: 40846

Categories

Category: Grass or Grasslike
Category: Aquatic