Credit: USDA-NRCS PLANTS Database / Britton, N.L., and A. Brown. 1913. Illustrated flora of the northern states and Canada. Vol. 2: 33. | USDA | License: PD USDA

Credit: I.Sá?ek, senior | Own work | License: PD

Credit: Britton, N.L., and A. Brown. 1913. Illustrated flora of the northern states and Canada. Vol. 2: 458. | USDA | License: PD USDA

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Credit: Anton Hartinger | Atlas der Alenflora. http://www.archive.o... | License: PD Old

Credit: Hitchcock, A.S. (rev. A. Chase) | http://plants.usda.g... | License: PD US Government PD USDA NRCS

Credit: Britton, N.L., and A. Brown. 1913. Illustrated flora of the northern states and Canada. Vol. 1: 174. | USDA | License: PD USDA

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Credit: Franz Eugen Köhler, Köhler's Medizinal-Pflanzen | List of Koehler Imag... | License: PD Old

Credit: Steve Hurst @ USDA-NRCS PLANTS Database | USDA | License: PD USDA

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Credit: Photo by and (c)2008 Derek Ramsey (Ram-Man) | Own Picture. | License: GFDL-1.2

Credit: Britton, N.L., and A. Brown. 1913. Illustrated flora of the northern states and Canada. Vol. 2: 496. | USDA | License: CC-BY-2.5 CC-BY-SA-3.0-migrated GFDL

Credit: Britton, N.L., and A. Brown. 1913. Illustrated flora of the northern states and Canada. Vol. 2: 91. | USDA | License: PD USDA

Credit: Britton, N.L., and A. Brown. 1913. Illustrated flora of the northern states and Canada. Vol. 3: 457. | USDA | License: PD USDA

Credit: Britton, N.L., and A. Brown. 1913. Illustrated flora of the northern states and Canada. Vol. 3: 457. | USDA | License: PD USDA

Credit: Hitchcock, A.S. (rev. A. Chase). 1950. Manual of the grasses of the United States. USDA Misc. Publ. No. 200. Washington, DC. 1950. | USDA | License: PD USDA

Credit: Hitchcock, A.S. (rev. A. Chase). 1950. Manual of the grasses of the United States. USDA Misc. Publ. No. 200. Washington, DC. 1950. | USDA | License: PD USDA

Credit: USDA-NRCS PLANTS Database / Britton, N.L., and A. Brown. 1913. Illustrated flora of the northern states and Canada. Vol. 3: 209. | USDA | License: PD USDA