  It has been suggested that the detection of a wealth of very low amplitude
modes in Delta Sct stars was only a matter of signal--to--noise ratio. Access
to this treasure, impossible from the ground, is one of the scientific aims of
the space mission CoRoT, developed and operated by CNES. This work presents the
results obtained on HD 50844: the 140,016 datapoints allowed us to reach the
level of 10^{-5} mag in the amplitude spectra. The frequency analysis of the
CoRoT timeseries revealed hundreds of terms in the frequency range 0--30
d^{-1}. The initial guess that Delta Sct stars have a very rich frequency
content is confirmed. The spectroscopic mode identification gives theoretical
support since very high--degree modes (up to ell=14) are identified. We also
prove that cancellation effects are not sufficient in removing the flux
variations associated to these modes at the noise level of the CoRoT
measurements. The ground--based observations indicate that HD 50844 is an
evolved star that is slightly underabundant in heavy elements, located on the
Terminal Age Main Sequence. The predominant term (f_1=6.92 d^{-1}) has been
identified as the fundamental radial mode combining ground-based photometric
and spectroscopic data. This work is based on observations made with ESO
telescopes under the Large Programme LP 178.D-0361.
