Musnad Ahmad 5:153

Mu'awiyah ibn 'Amr and Abu Sa'id narrated to us, they said: Za'idah narrated to 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)." Abu Sa'id said: "Palm fiber."