Resume of Original Article in Japanese

Abstract

The stem of Alsopルila acaulis is characterised by the creeping habit, running horizontally through the ground. It has, in a largest one, 20 cm. in length and 3 cm. in diameter, and the leaves are small less than 1.5 m. in length, so that the general form looks like the most of the Phypodiacean species. But, the internal. structure of the rhizome, as well as the leaf, shows the typical Cyatheacean type. The main stele of the rhizome is constructed in a dictyostelic form, each meristele enveloped by the characteristic sclerenchymatous bands, and the medullary strands, less than ten in number in a level, are also accompanied by the same tissue. They are originated in the pith and run through up to a leaf gap, to which they are comュ municated. In the petiole, a few pairs of vascular strands are arranged in an arc, but at least one pair is situated projecting somewhat inwards, showing the characteristic Cyatheacean type. In spite of the dorsiventrality of the rhizome, al of the tissues are constructed in a radial form. So far as the external forms are concerned, this plant is similar to the Polypodiacean species, but its internal structure of the vegetative organs, as well as the sporangial character show the characteristic features of Alsophilan species, so that it will be an interesting instance of Alsophila with a creeping rhizome.