  We study morphology and luminosity segregation of galaxies in loose groups.
We analyze the two catalogs of groups which have been identified in the Nearby
Optical Galaxy (NOG) sample, by means of hierarchical and percolation
``friends-of-friends'' methods (HG and PG catalogs, respectively). In the first
part of our analysis we consider 387 and 436 groups of HG and PG, respectively,
and compare morphology- (luminosity-) weighted to unweighted group properties:
velocity dispersion, mean pairwise distance, and mean groupcentric distance of
member galaxies. The second part of our analysis is based on two ensemble
systems, one for each catalog, built by suitably combining together galaxies of
all groups (1584 and 1882 galaxies for HG and PG groups, respectively). We find
that earlier-type (brighter) galaxies are more clustered and lie closer to the
group centers, both in position and in velocity, than later-type (fainter)
galaxies. Spatial segregations are stronger than kinematical segregations.
These effects are generally detected at the larger than 3-sigma level.
Luminosity segregation is shown to be independent of morphology segregation.
Our main conclusions are strengthened by the detection of segregation in both
hierarchical and percolation catalogs. Our results agree with a continuum of
segregation properties of galaxies in systems, from low-mass groups to massive
clusters.
