There are two ways to say the ferial Office of Wednesday Matins given in the Anglican Breviary. In scheme 1 for Matins the Office of Lauds to follow must be of Lauds 1. This means that the last three Psalms are said as is given on pages B83 to B85. In scheme 1 Psalm 50 is broken up in two parts and separated by Antiphons, which is followed by yet another Antiphon and Psalm 51 entire.
Whenever Lauds is said according to lauds 2 the Office of Matins on Wednesday changes. Matins is said according to scheme 2 (p. B85-86). That means that the last three Psalms to be said are now Psalm 50 broken up in three parts separated by Antiphons. Psalm 51 is not said in Matins at this time. This is so because psalm 51 is said as part of the Office of Lauds whenever Lauds is said of Lauds 2. Therefore in saying the Office of Matins on Wednesdays during Lent it must be said according to scheme 2.
Gregory +
The Anglican Breviary 