An experimental study under 1 bar pressure with ƒO₂ monitoring has been performed on rhönite-bearing basanitoïde, hawaiite and pure kaersutite from the alkalibasalt series of the Devès (French Massif Central). The following assemblages are recorded to lower temperatures : -NNO buffer (1) Kaersutite ol + (sp) + plag + rhönite + cpx + mt + liq (2) Basanitoïde ol + (sp) + cpx + mt + plag + rhönite + liq (3) Hawaiite ol + (sp) + plag + cpx + mt + liq -IW buffer (4) Kaersutite ol + (sp) + cpx + plag + rhönite + liq (5) Basanitoïde ol + cpx + plag + rhönite + liq (6) Hawaiite ol + cpx + plag + liq Spinel reacts with liquid to give plagioclase (cases 1, 3 and 4) and magnetite (cases 2 and 3). The liquidus temperatures of the kaersutite (1310 °C) and the basanitoïde (1 300 °C) do not vary significantly with ƒO₂ contrary to the liquidus temperature of the hawaïte : 1 195 °C for NNO and 1 255 °C for IW. The crystallization course for the basanitoïde shows spinel and clinopyroxene may coexist (at equilibrium) under 1 bar. The temperature of crystallization of rhönite is independent of the ƒO₂ between NNO and IW buffers and it seems rather controlled by the bulk composition of the sample : 1 170 °C for the kaersutite versus 1 100 °C for the basanitoïde. This petrographic study and experimental results together with available and petrographic data dealing with rhönite-bearing and melilite-free lavas suggest that the crystallization of rhönite and its coexistence with plagioclase is controlled by the rock bulk composition (chiefly Ti and Ca) and by early crystallization and Ti content of clinopyroxene depending on pressure.