Musnad Ahmad 5:82

Abu Usamah narrated to us, Zaidah informed us, 'Ata' ibn al-Sa'ib narrated to us, from his father, from Ali, who said: "The Messenger of Allah, peace and blessings of Allah be upon him, prepared Fatimah with a velvet blanket, a water skin, and a leather pillow stuffed with idhkhir (lemon grass) fiber."