178 BOTANICAL GAZETTE [MARCH 
THE SPORELING. 
Many if not all of the eggs of Sargassum on leaving the conceptacle 
become fastened immediately by the mucilaginous wall of the oocyst, 
which still surrounds it, to the surface of the reproductive branch. In 
this position the eggs segment. ‘The first division of the egg in Sar- 
gassum does not differentiate a rhizoidal region, as in Fucus and 
Ascophyllum. Instead, a many-celled ellipsoidal structure is formed, 
the divisions occurring with mathematical precision. Rhizoids then 
develop at one end with no apparent relation to a substratum or to 
gravity, so far as could be observed in fixed material. Sporelings 
sometimes occur at opposite sides of a branch with rhizoids directed 
toward the stem, thus showing no relation in the development of rhi- 
zoids to gravity; and again, sporelings occur with rhizoids directed 
away from the branch in various directions, indicating that the 
parent plant exerts no special influence. It is possible that the 
attachment of a sporeling upon a plant is so insecure that the 
direction of its axis may be shifted in the manipulation of material. 
Otherwise it is difficult to account for the conditions which were 
observed. 
When the many-celled sporeling has reached the condition for rhi- 
zoid formation the cells at one pole elongate, thereby giving rise to a 
tuft of rhizoids of approximately equal length. This mass of rhizoidal 
filaments finally produces the characteristic disk-shaped holdfast of 
the mature plant. Fig. 32 shows a sporeling in about the oldest con- 
dition in which it remains attached to the parent plant. No apical 
cells were found in these sporelings and therefore its differentiation 
must occur after the sporeling has separated from the parent 
plant. 
The germination of the oospore deserves careful cytological investi- 
gation. Many preparations have been made and studied, but further 
attention will be given the subject before the observations are pub- 
lished. A few conditions may be noted, however. There are numer- 
ous radiations at the poles of the early spindles. The asters contain 
granular inclusions which suggest centrosomes, although their origin 
and relation to the processes of mitosis have not been traced. Walls 
following the mitoses are developed somewhat slowly, being formed in 
part at least by the membranes of contiguous vacuoles. 
