Embryological Studies on Eusargassum. (Preliminary Note)

Abstract

i) The present paper dealt with an embryological study on two species of the subgenus Eusargassum (Sargassum I and Sargassum IV), whose specific names were not yet known. As to the mauler of rhizoid formation of embryos, one species (Sargassum I) belongs to the 16-cell type, and another (Sargassum IV) to the irregular 8-cell type. In Eusargassum, therefore, two types of rhizoid formation (the 16-cell type and the irregular 8-cell type) are distinguishable.
ii) Generally speaking, these two types are commonly found in Sargassum, whereas the radial-8-cell type to which only S. Horneri belongs, is rather exceptional.
iii) In this subgenus, similarly with cases of other species of Sargassum, the eggs of the irregular 8-cell type are much smaller than those of the 16-cell type.