(a) It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) prayed in open ground, with nothing in front of him.
(b) There is a supporting narration (shahid) for this hadith, more authentic than it, reported from Sayyiduna al-Fadl bin Abbas (may Allah be pleased with them both).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 3480