One can readily learn to recognize many of the grasses, both cultivated and wild. It is not necessary to have any elaborate instruments for examining them or to acquire any detailed knowledge of their structure. Nearly every grass is so distinctive that once a person has noted its obvious characteristics he will easily recognize it again. Though there are probably 6,000 distinct species of grasses in the world, only about 60 are important cultivated plants, and not more than 20 wild species are abundant or valuable in any one locality.