Nowadays the majority of commercial alloys are multicomponent and multiphase systems. The understanding and prediction of microstructure formation in multicomponent alloys is complex, especially when multiphase reactions occur along the solidification path. Particularly, several efforts are directed towards controlling the amount, the morphology and the distribution of minority phases, formed in situ as particles or inclusions. Present research focuses on the investigation of the eutectic growth in ternary aluminium alloy. At certain solidification conditions the Al-Mn-Si ternary alloy exhibits a special type of univariant eutectic growth as separately nucleated AlMnSi- particles at the advancing Al-interface during directional growth. Repetitive pushing and engulfment of in situ generated intermetallic particles at the solid/liquid interface leads to the formation of a banded structure. This rather unusual eutectic type of univariant eutectic structure is explained by the symbiotic eutectic growth hypothesis.