Which of these names is a genus of plant that consists of grass species:  Poa or Gymnocladus?
Gymnocladus Gymnocladus (Neo-Latin, from Greek γυμνὀς, "gymnos", naked + κλάδος, "klados", branch) is a small genus of leguminous trees. The common name coffeetree is used for this genus.
Poa arida Poa arida is a species of grass known by the common names plains bluegrass and prairie speargrass. It is native to North America, where it occurs throughout western and central Canada and the central United States. It is most common east of the Continental Divide; specimens west are often misidentifications.