| Poaceae | Diarrhena americana | Eastern Beakgrain | Rich moist forests, usually over calcareous rocks. | W. VA and WV west to IN, south to TN, sw. NC, and nw. GA (Jones & Coile 1988); disjunct west of the Mississippi in MO, AR, and OK. | 
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| Poaceae | Diarrhena obovata | Western Beakgrain | Alluvial forests, other moist forests. | Sw. PA and IN west to SD, KA, south to w. VA, c. TN, and ne. TX. First reported for VA by Fleming & Ludwig (1996). The floodplain of the Potomac River (in Fairfax County, VA) has a number of disjuncts of species with more midwestern affinities, including Diarrhena obovata, Erigenia bulbosa, Valeriana pauciflora, and Erythronium albidum (Fleming & Ludwig 1996). | 
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