九州北西部・本州西端部の標高300m以下の13地区のシバ草原は, 他地域の群落との比較にもとづいて, シバーツボクサ群集と認められた。その発達領域はシイ林域にあり, 標徴種ツボクサとハイメドハギにより, シバ群団の他の群集より区別される。本群集は, ハマゼリー, 典型一, トダシバー亜群集をふくみ, 前二亜群集は塩風の影響をうける沿岸部に発達する。ハマゼリ亜群集は, ダルマギクーおよび典型一変群集に区分され, 前者は海にもっとも近くかつ放牧家畜の影響が少ない傾斜地にあり, 海岸植物を多くふくむ。典型変群集および典型亜群集は緩傾斜地ないし平坦地に発達し, 家畜による影響が強集, 沿岸部放牧草原の広い面積を占める。トダシバ亜群集は塩風の影響をうけず, 1kmないし5km内陸の丘陵地に発達する。Based on phytosociological and ecological studies of low-elevation grazed grasslands in northwestern Kyushu and on a comparison of them with related communities, the Zoysia japonica community found in the area studied was recognized as a new association of Zoysion japonicae and was named Centello-Zoysietum japonicae. The association is found only in lowland areas of the warm-temperate region. It is characterized and differentiated from the four associations of the alliance described by SUGANUMA (1966) by the presence of two character species, Centella asiatica and Lespedeza cuneata var. serpens, and by the absence of the character species of SUGANUMA\u27s four associations. The Centello-Zoysietum is subdivided into three subassociations : Subass. of Cnidium japonicum, Typical Subass. and Subass. of Arundinella hirta. The first two subassociations are located on coastal areas influenced by salt spray from the sea. The Subass. of Cnidium japonicum is further subdivided into Variant of Aster spathulifolius and Typical Variant. The former variant is restricted to steeper slopes under lighter grazing and trampling by animals, while the Typical Variant and the Typical Subass. occupy gentle slopes and fiat sites which are heavily disturbed. The Subass. of Arundinella hirta is found on hills, 1 km to 5 km from the sea.Without Tables. For Table1 and Table 2, see http://ci.nii.ac.jp/naid/110001881395
