American slough grass (slough grass)
Beckmannia syzigachne (Steudel) Fernald

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American sloughgrass is characteristically found in damp habitats such as wet ground or shallow water and at the margins of ponds, lakes, and streams but may also grow along ditches. It is considered a good forage grass (Tzvelev 1983), but it typically grows in sites that would be easily damaged by grazing. Its Iowa distribution is limited to the furthest northwestern counties, in the lake district, where the species can be seen in flower from mid-June to August. Despite its common name here, this species is native to both North America and Asia. This species is readily distinguishable from all other wetland grasses by the strongly flattened spikelets that are round in side view and tightly packed in two rows along the branches of the flowering head. American sloughgrass is a very attractive species that probably deserves horticultural consideration for planting in wetter areas; at least in Russia, this species is also noted for its tolerance of high soil salinity (Tzvelev 1983).

Etymology: : Beckmannia is named for Johann Beckmann, an 18th century German botanist and author of one of the first botanical dictionaries; syzigachne is from the Greek syzygos for "joined" and achne for “chaff,” referring to the prominent glumes that stay joined when the whole spikelet falls from the flowering head.


Plants annual, tufted, erect. Culms 40-100 cm. Leaves mainly along the stem; sheaths smooth, hairless; ligules 2.5-8 mm long; blades 6-20 (-25) cm long, 0.3-1 (-1.3) cm wide, flat, rough to the touch. Flowering heads 12-24 (-37) cm long, consisting of 15-20 appressed or ascending branches (these often not easily distinguished), each bearing few to several branchlets with tightly packed spikelets in two rows. Spikelets 2.3-3 mm long, 1.8-2.2 mm wide, round to ovate in side view, with 1 fertile floret (a second well-developed floret occasionally present), the entire spikelet falling when ripe. Glumes alike, appearing inflated but strongly keeled, 3-veined, ending abruptly in a small, slender point; lemma 2.4-3.5 mm long; anthers pale yellow. Chromosome number 2n = 14.


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