Which is in the grass family, Pachypodium or Arrhenatherum?
Arrhenatherum Arrhenatherum, commonly called oatgrass or button-grass, is a genus of Eurasian and North African plants in grass family.
Achnatherum Achnatherum is a genus of plants which includes several species of needlegrass. Several needlegrass species have been switched between "Achnatherum" and genus "Stipa"; taxonomy between the two closely related genera is still uncertain.