  We study the Floer cohomology of the Dehn twist along a real Lagrangian
sphere in a symplectic manifold endowed with an anti-symplectic involution. We
prove that there exists a distinguished element in the Floer group that is a
fixed point of the automorphism induced by the involution. Our methods of proof
are based on Mak-Wu's cobordism and Floer-theoretic considerations.
