467. 
Subfam. Nitophyllez. 
Phycodrys Kützing. 
1. Phycodrys rubens (Huds.) Batters. 
Batters, Cat. Brit. Mar. Algæ. 1902 p. 76. 
Fucus rubens Hudson F1. Angl. 1762 p. 475 (not seen). 
Fucus roseus O. Fr. Müller, Flora Danica tab. 652, 1775. 
Fucus sinuosis Gooden. & Woodw., Linn. Transact. III 1797 p. 111. 
Delesseria sinuosa (G. & W.) Lamour. Essai, 1813 p. 124, Lyngbye Hydr. 1819 p. 7 Tab. 2B; Harvey, 
Phye. Brit. III pl. 259, 1851; J. Agardh, 1852 p. 691; Magnus, Bot. Erg. d. Pommerania Exp. Kiel 
1873 p. 75; Nägeli u. Schwendener, Das Mikroskop, 2. Aufl. 1877 p. 563; Wille, 1885 pp. 30, 51, 
fig. 51, 1887 pp. 65—69 figs. 21—31; Kuckuck, 1894 p. 255; Phillips, 1898, p. 189. 
Phycodrys sinuosa (Huds.) Kützing. Phye. gen. 1843 p. 444 Taf. 68 II; Tab. phyc. XVI 1866 pl. 20; Kylin, 
1923 p. 64. 
The apical growth of the frond has been studied repeatedly (NAGELI and 
SCHWENDENER, WILLE, NIENBURG, KYLIN). NIENBURG has stated the occurrence of 
intercalary cell-divisions!, but the succession of the divisions and the genetic con- 
nection of the cells has only been correctly described by Kyrın (1923) who payed 
especial attention to the pits connecting the cells. In my figures 427 and 428 the 
pits connecting the cells have not been drawn. The sequence of the division walls 
can, however, to a certain degree be concluded from a comparison of the consecutive 
segments cut off from the apical cell, but the fact stated by Kyrın, that the prim- 
ary cell-row of the segment issues from the lowermost cell produced by intercalary 
division of the primary cell in the axial cell-row, cannot be recognized. Intercalary 
divisions occur early in the axial cell-row; they appear already in the second seg- 
ment from the top (Kyun figs. 44, 45) or a 
little later, in particular in narrow fronds (figs. 
427, 428), where the primary segments do not 
become so much deepened as in Kyrın’s fig. 44. 
The secondary initial cells situated in the 
upper edges of the primary segments are able 
to grow out into lobes, and as the two initial 
segments of a segment always behaye in the 
same manner, the lobes are always opposed. 
In the frond shown in fig. 427 the three con- D 
secutive segments produced each a lobe on 
2 3 Fig. 427. 
each side, and it seems to be normally so that Phycodrys rubens. Tip of frond. April. 260 :1. 
the number of lobes in a normal leaf corre- 
sponds to an equal number of consecutive segments. The distance between two 
consecutive lobes or between the nerves belonging to them in an adult leaf thus in- 
dicates the height obtained by the primary segments which may be 3-—6 mm. 
* SCHMITZ has undoubtedly observed these cell-divisions in Del. sinuosa, but he has not expressly 
cited this species in this connection. 
