Mana Based Spellcasting - additional known spells

You prepare the list of spells that are available for you to cast, choosing from the spell list for your class. When you do so, choose a number of spells equal to your primary ability modifier + your spell caster level (minimum of one spell). The spells must be of a level you can cast. The primary ability for Bards, Sorcerers, and Warlocks is Charisma. The primary ability for Clerics, Druids and Rangers is Wisdom.