fowl mannagrass
Glyceria striata (Lam.) Hitchc.

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inflorescencespikeletillustration

Glyceria striata grows throughout most of North America in freshwater wetlands and along streams. Throughout its range, it shows much variation, from tall, robust plants with nearly succulent culms and open flowering heads to short plants with erect, tough culms and relatively closed flowering heads. Fowl mannagrass can be found throughout Iowa in marshes, wet banks, and damp woods, but also occasionally in shallow water—it is by far the most common of the Glyceria species in the state. Of the four species of Glyceria in Iowa, this one is most easily confused with American mannagrass (Glyceria grandis), as both have relatively short spikelets (less than 1 cm) that are flattened. Fowl mannagrass has first glumes 0.5-1 mm long and two stamens per flower, whereas American mannagrass has first glumes 1.2-2 mm long and three stamens per flower. Many species in this genus are planted in and around aquatic gardens because they have attractive open flowering heads such as seen in this species. Spikelets in this genus tend to shatter relatively quickly once the grains are ripe, so it is often difficult to find complete spikelets later in the growing season.

Etymology: Glyceria from the Greek glukeros = sweet, referring to the sweet seed of the type species; striata from the Latin stria = fine linear marking, line, streak, or groove, referring to the prominent veins on the lemmas

 

Plants perennial, rhizomatous. Culms (30-) 50-125 cm, erect or the bases reclining but with the tips ascending, often somewhat succulent. Leaves with the sheaths closed for most of their length, smooth to minutely roughened; ligules 1-4 mm long, rounded (sometimes abruptly pointed to acute), margins irregularly toothed or cleft; blades 13-30.5 cm long, 2-8 mm wide. Flowering heads 8-21 cm long, open, nodding; branches straight to lax, the lower ones widespread to drooping. Spikelets 2.6-3.6 mm long, 1.4-2.5 mm wide, with 4-6 florets. First glume 0.5-1 mm long; second glume 0.8-1.2 mm long; lemma 1.5-2.1 mm long, minutely roughened, the veins raised, the apex acute, somewhat hood shaped; palea slightly shorter than or equaling the lemma; anthers 2. Chromosome number 2n = 20 (reports of 28 are considered dubious).

 

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