Woodworth. — The Apical Cell of Fucus. 209 
small irregular cells already spoken of which form the hyphae 
of the stem. The segments cut off from the sides of the 
initial cell may be called lateral segments. Besides the 
lateral segments the base of the apical cell is cut off, form- 
ing a basal segment , which by secondary division produces 
cells which belong to those smaller cells producing the 
hyphae. 
Thus lateral segments of the initial cell give rise to epi- 
dermal cells and cells of the central tissue, while basal seg- 
ments of the initial cell go to form cells of the hyphae only, 
or all of that tissue covered by the epidermis. The segments 
are cut off from the initial cell successively as basal, right, 
left, and so on, figures 1 and 2. 
Fucus VESICULOSUS, L., AND F. FILIFORMIS, Gmelin. 
The facts above given for F. furcatus were confirmed by 
sections of F. vesicidosas and F. jiliformis. My work was 
especially confined to F. furcatus , because of the more excellent 
material I had of that species. 
In F. vesiculosus the initial cell is not so marked in shape 
as in F. furcatus , it being more blunt at the upper or free end, 
and on the whole more of a quadrilateral. Its large size 
relative to the surrounding cells is the same. 
In F. filiformis the terminal depression is not so elongated 
as in either of the two other species owing to the more pointed 
and rounded shape of the tip. The initial cell in this species 
has the same characteristics as in the other two, but is, 
however, somewhat broader for its height. 
The existence of a single apical or initial cell in Fucus 
is in every way consistent with what has been found for 
other members of the group by Kny 1 , Reinke 2 , and Val- 
liante 3 . 
1 Botanische Zeitung, vol. xxxiii. (1875), No. 27, p. 450. 
2 J. Reinke, Beitrage zur Kenntniss der Tange, in Pringsheim’s Jahrb. fur Wiss. 
Botanik, x. (1876), p. 341. 
3 R. Valliante, Fauna und Flora des Golfes von Neapel. Le Cystoseirae del 
Golfo di Neapoli. Leipzig, 1883. 
