Dactylis glomerata

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Orchardgrass is an introduced species native to Eurasia and Africa that now occurs throughout North America. This species is commonly grown as a cool-season forage crop for livestock and as a high quality pasture and hay crop in the United States, often in a mixture with a legume such as alfalfa. While orchardgrass may be used by wildlife, it is listed as an invasive species in some areas (Stubbendieck et al. 1994; Uva et al. 1997). Although not documented in every county in Iowa, orchardgrass is found throughout the state, most commonly in meadows, lawns, and along roadsides. Orchardgrass blooms in May and June but occasionally flowering heads may be seen as late as September. This grass is easy to recognize when in flower because the spikelets occur in dense clusters towards the tips of the stiff branches. The plants grow in clumps, often forming large tussocks with a characteristic pale green color. Early in their growth, leaves are strongly flattened and they have a soft texture. The leaf sheath with fused margins is also characteristic, but the line of fusion is weak and the sheaths often split open, especially in older stems.

Etymology: Dactylis from the Greek daktylos = finger; glomerata from the Latin glomeratus = collected closely to the head, referring to the clustered spikelets.


Plants perennial, tufted, sometimes with short rhizomes. Culms 35-120 cm, erect, hollow; tillers emerging from within the basal sheaths. Leaves with the sheaths closed toward the base with margins fused; ligules membranous, 3-8 mm long; blades 9-37 cm long, 3-8 mm wide, linear, flat to folded, midvein conspicuous and white. Flowering heads terminal, held above the leaves, 5-23 cm long, 1-8 cm wide, oblong when young, pyramidal at pollination, with relatively few major branches, the lower branches spreading; primary branches naked at the base, bearing dense clusters of spikelets at the tips. Spikelets 6.5-8.3 mm long, 2-3.5 mm wide, with 3-5 florets, strongly flattened, stalks short; glumes shorter than the spikelet, equal or unequal, 4-7 mm long, awn-tipped, keels usually ciliate; lemmas 6-7.2 mm long, smooth to hairy, keels ciliate, with an awn up to 1 mm long. Chromosome number 2n =14, 21, 27-31, 42.


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