  We analysed the wide-field near-infrared survey of the Praesepe cluster
carried out by the UKIRT Infrared Deep Sky Survey (UKIDSS) Galactic Clusters
Survey (GCS) and released by the Data Release 9 (DR9). We compare our Praesepe
mass function (MF) with the ones of the Pleiades, alpha Per, and the Hyades. We
also present preliminary results of a spectroscopic follow-up for the low mass
members (M=<0.1Msol) in Praesepe, alpha Per and Pleiades using the Optical
System for Imaging and low Resolution Integrated Spectroscopy (OSIRIS) mounted
on the 10.4m Gran Telescopio Canarias (GTC). We also present the optical
spectrum of the first L dwarf in Praesepe.
