Hadith.135 - Abu Basir narrated from Imam Jafar ibn Muhammad Al-Sadiq (as) regarding a man who forgets to wipe his head during wudu.
Imam (as) said
"Then let him wipe it."
Abu Basir asked: "What if he does not remember until he has started the prayer?"
Imam (as) said: "Then let him wipe his head with the moisture from his beard”.