Grasses of the Eloise Butler Wildflower Garden

Fowl Mannagrass is a variable sized perennial with stems (culms) being 12 to 50 inches high. Some plants will be slender and tall with open flowering heads while in other locations a plant may short and stout with relatively closed heads.

The leaf blades are flat, often folded into a shallow M or W shape, erect to ascending, up to 12 inches long and up to 3/16 inches wide (2 to 6 mm) - this would be shorter and narrower than American Mannagrass, G. grandis. The upper surface is usually a bit rough.

Sheaths & Ligules: The leaf sheath is smooth to slightly rough, keeled, and closed for most of its length. The ligule is short, up to 4 mm long, and usually rounded. Both sheath and ligule are without hair.

Inflorescence: The flowering heads are panicles 2.5 to 8 inches long (6-25 cm) and almost as wide at the base. Branches of the panicle can be ascending at their base, but lower branches are widespread, divergent and drooping at maturity. Panicle branches have 15 to 50 spikelets, usually crowded in the upper 2/3 rds of the branch.

Spikelets are 1.8 to 4 mm long and 1.2 to 2.9 mm wide, flattened, oval in side view, and containing 3 to 7 florets. There are two short whitish glumes with raised veins; the glumes 1.5 times longer than wide, the lower shorter, length from 0.5 to 1.0 mm long. The lemmas are about 2 mm long, ovate in front view, purplish and have 7 prominent nerves. Anthers number 2, purple or yellow.

Varieties: Some authorities recognize two varieties - var. striata and var. stricta - depending on stem thickness and leaf blade width, but Minnesota authorities do not recognize these as separate plants.

Habitat: Fowl Mannagrass is found in the moist areas of shorelines, marshes, wetlands, moist wood and occasionally in shallow fresh water. It grows from a rhizome and forms tussocks.

Names: The genus name, Glyceria, is Greek for 'sweet', which is the taste of the grain and which is palatable. The species name, striata , means 'striped', referring the the prominent veins of the lemmas. The common name "mannagrass" is a somewhat biblical reference. An older no longer accepted name is Glyceria nervata.

The author names for the plant classification are as follows: The first to publish a classification was ‘Lam.’ which refers to Jean-Baptiste Lamarck (1744-1829) French naturalist and biologist, an early proponent of evolution who among other things, published the 3 volume Flore Francaise. He is best known for his theory of the inheritance of acquired characteristics. His work was amended by ‘Hitchc.’ which refers to Albert Spear Hitchcock (1865-1935) American botanist and agrostologist (one who studies grasses). He worked for USDA, authored more than 250 works, including the important Manual of the grasses of the United States.

Comparisons: There are two Glyceria species in the Garden - G. grandis, American Mannagrass, and G. striata. They are both plants of wet or moist areas. The two species can be easily confused with each other as both have spikelets that are short (less than 1 cm) and flattened. The key differences are in the details of the glumes and spikelet length, which is much longer in G. grandis. American Mannagrass also has leaf sheaths that are open for over half of their length, flowering heads are longer, 6 to 16 inches long (16 to 42 cm), branches spreading to drooping. One of the other more confusing species in North America will be G. elata, which exists in the western part of the range of G. striata. However, G. elata is a larger plant with larger panicles, spikelets 3 to 6 mm long instead of 1.8 to 4 mm. Without looking at specifics, the two plants look alike.