Abu Bakr brought his father Abu Quhafa before the Messenger of Allah ﷺ, and his head was white like the thaghamah plant. The Messenger of Allah ﷺ said, "Change the color of this hair of his."
دخل بأبي قحافة أبو بكر على رسول الله ﷺ ورأسه كأنه ثغامة فقال رسول الله ﷺ: غيروا هذا من شعره.
Ahmad (26956), Ibn Hibban (7208), Hakim (3/46-47), and Bayhaqi (9/121-122) all narrated it from the hadith of Ibn Ishaq, who said, Yahya bin Abbad bin Abdullah bin Zubayr told me, from his father, from his grandmother Asma bint Abu Bakr, who said... and she mentioned it within a lengthy account, which has already been given in its proper place.His saying, "thaghamah," with the letter tha (pronounced with fatha) and ghayn. Abu Ubayd said, it is a plant with white flowers and fruit, to which the whiteness of gray hair is likened. Ibn Arabi said, it is a tree that turns white as if it were salt. Nawawi mentioned this in his commentary on Sahih Muslim.