Musannaf Ibn Abi Shayba 27:79

Abu Khalid al-Ahmar narrated to us, from Humayd, from Anas, that the Messenger of Allah (may Allah bless him and grant him peace) said: "When I reached the Lote Tree of the Utmost Boundary (Sidrat al-Muntaha), its leaves were like the ears of elephants, and its fruits were like large jars (qilal). When that which covered it from the command of Allah covered it, it transformed, and I mentioned rubies."