Parasympathetic ganglia

Parasympathetic ganglia are the autonomic ganglia of the parasympathetic nervous system. Most are small terminal ganglia or intramural ganglia, so named because they lie near or within (respectively) the organs they innervate. The exceptions are the four paired parasympathetic ganglia of the head and neck.
Of the head and neck.
These paired ganglia supply all parasympathetic innervation to the head and neck.
Roots.
Each has three roots entering the ganglion and a variable number of exiting branches. 
Some ganglia also carry special sensory fibers (SVA) for taste sensation.