Ja'far bin Rabi'ya bin Shrhbyl جعفر بن ربيعة بن شرحبيل · The Book of Salah

"The Messenger of Allah (ﷺ) used to stand in Zuhr and recite the equivalent of thirty verses in each Rak'ah, then in the first two Rak'ahs of 'Asr he would stand for the equivalent of fifteen verses."