大牟田市の1干拓地に自生するヒロハマツナについて

抄録

The following results have been obtained by an investigation of the Hirohamatsuna grown in autogeny on some parts of the drained land in Omuta City, in September, 1958. (1)In the middle area, Hirohamatsunas are distributed almost in preference to other plants, and the reeds are distributed around them on the three sides of east, west and south-as if to embrace them. The view reminded one of habitat segregation autogeny of Hirohamatsunas and reeds. (2)From the middle to the bank, a succession of plants seemed to be visible namely, in the middle parts, Hirohamatsunas monopolizingly autogenied in the area, and their growth and frequency was great, but the nearer they were to the bank, the less frequent and grown-up they seemed to be, finally they completely disappeared. According as the Hirohamatsunas were more less frequently seen, the more of the reeds appeared to make their appearance. Further their growth became. better and better until the land was solely occupied by reeds. (3)As for Hirohamatsunas, they make remarkable changes in frequency, growth, and form according to their environments. Frequency becomes greater in the following orders, current coast, sea-water invading area, dry-land area. Their growth rather makes a contrary phenomenon, being in a better state in the current (washing) coast. Therefore, sea-water seems to make great difference to their growth, and yet, it has been found that, the sloping dry land fusing south adjoining, to the current-coast seems to be better-fitted for their growth than the latter. Those grown in the current-coast are slender in form, those in the tide invaded-area thick set, those in the dry-land, neat and small. Being closely(grown)and mixedly grown among others, its twigs are few in number and so their lengths and expansions become less.