Musannaf Ibn Abi Shayba 3:575

'Abbad ibn al-'Awwam narrated to us, from al-Shaybani, from 'Abdullah ibn Shaddad, he said: Maymunah narrated to me, she said: The Messenger of Allah (peace and blessings of Allah be upon him) used to pray while I was beside him, and sometimes his garment would touch me when he prostrated. And he used to pray on the khumrah (a small prayer mat made of palm leaves).