In Benard-Marangoni convection in a square vessel, of small aspect rat
io, a sequence of bifurcations is observed as control parameters are s
lightly changed. Some of the emerging patterns are stationary and othe
rs are oscillatory in nature. The stationary patterns break the symmet
ry and the oscillatory ones can be classified in three kinds. We show
that this dynamics can be explained assuming that the system is close
to a Takens-Bogdanov bifurcation.