Sahih Muslim 2967 c
Khalid b. Umair reported:
I heard Uqba b. Ghazwan as saving: I found myself as the seventh amongst the seven who had been along with Allah's Messenger (ﷺ). We had nothing to eat but the leaves of hubla (a wild tree) until the corners of our mouths were injured.
وَحَدَّثَنَا أَبُو كُرَيْبٍ، مُحَمَّدُ بْنُ الْعَلاَءِ حَدَّثَنَا وَكِيعٌ، عَنْ قُرَّةَ بْنِ خَالِدٍ، عَنْ حُمَيْدِ،
 بْنِ هِلاَلٍ عَنْ خَالِدِ بْنِ عُمَيْرٍ، قَالَ سَمِعْتُ عُتْبَةَ بْنَ غَزْوَانَ، يَقُولُ لَقَدْ رَأَيْتُنِي سَابِعَ سَبْعَةٍ
 مَعَ رَسُولِ اللَّهِ صلى الله عليه وسلم مَا طَعَامُنَا إِلاَّ وَرَقُ الْحُبْلَةِ حَتَّى قَرِحَتْ أَشْدَاقُنَا ‏.‏