We have done the ecological study of vegetation landscape based on the symphytosociology in Yokohama and Yokosuka of Kanagawa Prefecture where the potential natural vegetation differs. The vegetation landscape structures of the two cities were comparatively analyzed, and the following four vegetation landscape units were classified: the Cryptomeria=Querceto acutissimo-serrato geosigmataxon in the green spaces of the Satoyama in Yokohama, the Rubo=Daphno-Querco geosigmataxon in the remaining green spaces of Yokosuka, the Pinellio-Euphorbieto geosigmataxon in the productive green spaces of both cities, the Bryo-Sagino geosigmataxon in the urban areas of both cities. The differential elements of the four geosigmataxa were quantified, and an ecological attribute of each geosigmataxon was quantitatively evaluated by statistical analyses. As a result, the Bryo=Querceto acutissimo-serrato hyper-geosigmataxon that corresponds to the Bryo=Daphno-Querco hyper-geosigmataxon in Yokosuka was newly classified in Yokohama. A green-space ecosystem of urban areas functions in the hyper-geosigmataxon of each city.