Valmiki Ramayana Ayodhya Kanda Sarga 87 Shloka 21

रामश्च Rama as well as, सीता Sita, उभौ both, तां रात्रिम् that night, यस्मिन् where, शयितौ slept, तत् that, इंगुदीमूलम् foot of the ingudi tree, एतत् this only, तत् that, तृणं च grass bed, इदमेव this one only.

Here at the foot of the ingudi tree and upon that bed of grass both Rama and Sita rested that night.