Musannaf Ibn Abi Shayba 3:1644

Abu Bakr narrated to us, he said: Abbad bin al-Awwam and Ali bin Mushir narrated to us, from al-Shaybani, from Abdullah bin Shaddad, he said: Maymunah informed me, she said: The Messenger of Allah (peace and blessings of Allah be upon him) used to pray on the khumrah (a small prayer mat made of palm leaves).