When must a woman resume prayer after menstruation?

A woman must perform the prayers after she has purified herself from menstruation and has taken a ghusl (ritual bath). Her purification is recognized by one of two signs: seeing the white discharge (al-qassah al-bayḍā'), or complete dryness of the area from blood. If she has purified herself, she is obligated to pray the prayer whose time she became purified in, provided that she catches at least one unit (rak'ah) of its time, based on the saying of the Prophet (peace and blessings be upon him): "Whoever catches a rak'ah of the prayer has caught the prayer."