Studies on summer weeds with special reference to the analysis of their compositions. : (I) General reseaches of weeds in the field of Kanto and its neighbouring region.

Summary Summer weeds in the field of Kanto and its neighboring region were generally surveyed in 1946∼1948. In this districts summer weeds was found to have 91 kinds of weeds. The results ot researches are summarized as follows ; Name of weeds Percentage of weight Digitaria ciliaris pers. 40.5 Portulaca oleracea L. 10.9 Cyperus spp. 9.7 Mallugo stricta L. 5.7 Amaranthus blitum L. 2.9 Equisetum arvense L. 2.5 Polygonum nodosumpers 2.1 Acalypha australis L. 2.1 Panicum crusgalli L. 1.7 var. submutica Mey Other 82 weeds 21.9 Digitaria ciliaris pers may be from this table assumed absolutely predominant in this districts in the summer season.