De acuerdo con evidencias de carácter morfológico y molecular se presentan nuevas combinaciones o nuevos nombres para 77 táxones de Cinnagrostis, siete táxones de Deschampsia y 24 táxones de Peyritschia, así como la descripción de tres nuevos géneros, Greeneochloa P.M. Peterson, Soreng, Romasch. & Barberá, gen. nov. (subtribu Echinopogoninae), Paramochloa P.M. Peterson, Soreng, Romasch. & Barberá, gen. nov. (subtribu Calothecinae) y Laegaardia P.M. Peterson, Soreng, Romasch. & Barberá, gen. nov. (subtribu Calothecinae) con dos, dos y una especie respectivamente. Además de las 116 nuevas entidades taxonómicas, proporcionamos una clave para los géneros de gramíneas americanas tratadas actual o anteriormente en Calamagrostis o Deyeuxia y enmendamos los genéros Cinnagrostis y Peyritschia.

We thank the Flora Iberica (CGL2014–52787–C3–1–P, CGL2012–32914, CGL2017-85204- C3-1-P) and FPI fellowship BES-2012-053754 to P. Barberá; the National Geographic Society Committee for Research and Exploration (Grant No. 8848-10, 8087-06) for field and laboratory support; the Smithsonian Institution’s Restricted Endowments Fund, the Scholarly Studies Program, Research Opportunities, Atherton Seidell Foundation, Biodiversity Surveys and Inventories Program, Small Grants Program, the Laboratory of Analytical Biology; and the United States Department of Agriculture. We thank Neil Snow and Jesus Valdés Reyna for suggesting changes to the manuscript, Alice Tangerini and Victor Dudas for preparing the illustrations, and Guy Nesom for editing the final version

Based on morphological and molecular evidence we present new combinations or new names for 77 taxa of Cinnagrostis, seven taxa of Deschampsia, and 24 taxa of Peyritschia; and describe three new genera, Greeneochloa P.M. Peterson, Soreng, Romasch. & Barberá, gen. nov. (subtribe Echinopogoninae), Paramochloa P.M. Peterson, Soreng, Romasch. & Barberá, gen. nov. (subtribe Calothecinae), and Laegaardia P.M. Peterson, Soreng, Romasch. & Barberá, gen. nov. (subtribe Calothecinae) with two, two and one species, respectively. In addition to the 116 new taxonomic entities, we provide a key to the genera of American grasses presently or formerly treated in Calamagrostis or Deyeuxia and generic emendations for Cinnagrostis and Peyritschia.