Cortaderia jubata

Cortaderia selloana

Austroderia richardii

Tripidium ravennae
leaves and inflorescences clearly apart leaves reaching up to the inflorescences tussock relatively small tussock relatively small
inflorescence loose by more patent branches inflorescence usually female, sturdy and erect in winter inflorescence open, unilateral inflorescence open, unilateral
leaf sheath glabrous to hairy leaf sheath glabrous or somewhat hairy leaf sheath glabrous leaf sheath glabrescent, with long hairs at base of blade resembling a ligule
  Photo's Tripidium ravennae: © Guillaume Fried (Anses), France Version February 2021