It is narrated from the Mother of the Believers, Sayyidah Aishah (may Allah be pleased with her), that "the Prophet (peace and blessings be upon him) used to pray on a mat."
No one narrated this hadith except Hammad bin Mas'adah (may Allah have mercy on him), and the well-known version is that it comes from the narration of Hammad bin Salamah (may Allah have mercy on him).
Hadith Referenceالمعجم الأوسط / باب الميم / 7179
Hadith Takhrij«أخرجه الطبراني فى «الأوسط» برقم: 2075»