2 o 8 Woodworth . — The Apical Cell of Fucus. 
The conclusions to be drawn from the above are, that the 
cell A is an apical cell, the growing-point ; and that from it 
are produced all the tissues of the plant, consisting in Fucus 
of an epidermis and a central mass of hyphae. 
My studies bring me to such results that I cannot agree 
with Reinke and Rostafinski in believing that the growing- 
point of Fucus consists of a group of apical cells, or that 
there is even more than one. What I find for Fucus is con- 
sistent with what has been found for other genera of the order, 
such as Cystoseira and Sargctssum , in which the growing- 
point consists of a single apical cell. 
My figures differ so much from those of Reinke as to make 
explanation difficult, unless perhaps he obtained his material 
at a different season of the year from that in which I gathered 
mine. 
My figure I agrees with Rostafinski’s figure 9. In both 
there is the large triangular cell at the bottom of the pit, and 
the arrangement of the other cells is the same in each. My 
figures 2 and 3 correspond to figures 10 and 13 of Rosta- 
finski. There is here a close resemblance, the essential 
difference being that Rostafinski makes the ‘ Bildungszellen ’ 
B B B etc. of equal value, while in my figure the central cell 
A with convex sides alone can be regarded as a i Bildungszelle 5 
that has given origin to the lateral cells A', A" etc., which 
correspond to the £ randsichtige Segmenten 5 of Rostafinski. 
I have made a large number of sections through a great 
deal of material and have found this central cell with its 
characteristics constantly the same. It is marked by its large 
size, large nucleus, thin walls and denser protoplasm, and 
is very difficult to stain, not taking the colour like the sur- 
rounding cells. 
I will now consider the relations of the initial cell, and the 
origin from it of the tissues of the plant. The series of cells 
on either side of the central cell are derived from it by division. 
These are again divided by planes in three directions at right 
angles to each other, the upper portions become epidermis 
cells and the lower or basal parts pass into the mass of 
