Which is in the grass family, Pachypodium or Arrhenatherum?
Pachypodium Pachypodium is a genus of succulent spine-bearing trees and shrubs, native to Madagascar and Africa. It belongs to the dogbane family, Apocynaceae. "Pachypodium" comes from a Latin form from Greek "pachus" (thick) and "podion" (foot) (or Gk podos, root form of pous, foot), hence meaning "thick-footed".
Schizachyrium Schizachyrium is a widespread genus of plants in the grass family. The name is derived from the Greek words σχίζειν ("schizein"), meaning "to split," and ἄχυρον ("achyron"), meaning "chaff." It refers to either the glume or the toothed lemmas.