Musannaf Ibn Abi Shayba 36:46

Waki’ narrated to us, from Sufyan, from Salamah ibn Kuhayl, from al-Hasan al-‘Arani, from Hudhayl ibn Shurahbil, from ‘Abdullah regarding His saying: "The Lote Tree of the Utmost Boundary" (Sidrat al-Muntaha). He said: It is the center of Paradise, meaning its middle. Upon it are the surpluses of silk and brocade.