531 
a fertilization really takes place. Huco Craussen (1929) studied the behaviour of 
the nuclei and found that the vegetative cells of Phyll. Brodiei contain numerous small 
nuclei, about 2 w in diameter, containing 4 chromosomes, whereas “In den Zellen 
des Karpogons [?] und im Gewebe des Parasiten” nuclei with 8 chromosomes are 
frequently to be found, which makes it probable that the formation of the sporo- 
phytic generation is preceded by a fertilization. This process however was not observed. 
Nor has Kyrın (1930, p. 26) observed the fertilization process, but he has found 
a carpogonium fusing together with an auxiliary cell, N 
and he thinks that such a process only takes place when / VÆR) 
the carpogonium is fertilized. | 
Phyllophora Brodiæi is spread in all the Danish 
waters from the North Sea to Bornholm, from 1 to 36 
metres” depth, attached to stones and sometimes to shells 
of bivalves. In the North Sea and Skagerak there are 
only few places where it thrives well (Bragerne); the 
frond is here fairly broad but only attains a height of 
10 cm. It scarcely becomes higher in the northern 
Kattegat where it is much less common than Ph. mem- 
branifolia. In the inner waters it attains its best develop- 
ment and is often abundant. Its maximal height increases 
considerably, as will be seen from the following figures 
indicating the maximal heights observed in the respec- 
tive waters: Ke 15 cm, Ks 17.5 cm, Sa 24 cm, Lb 34 cm, 
Sb 29 cm, Su 23. In the Baltie it is much smaller: Bw 
11 cm, Bb 8 cm. Its appearance varies not only as to 
the size but also otherwise, according to the different none ee Dre 
mode of ramification and the varying breadth of the sermlings from the walls and the 
frond. There is, however, no reason to describe special bottom of ea te an 
varieties because the differences seem to depend on outer 
conditions, and I am not able to point out types that might be supposed to be 
genotypically distinct. As mentioned above, there are two modes of ramification: 
dichotomy and proliferation, which are usually both in function; but it may happen 
that one of them is predominant. When the ramification is chiefly or exclusively 
dichotomous, which happens particularly with broad fronds (fig. 498), the shape may 
come near to the arctic f. interrupta, characterized by the frond being alternately 
broad and narrow, but the typical f. interrupta hardly occurs in the Danish waters; 
the specimen most resembling it was met with in a bank south of Lyo, Lille 
Belt, in 22 metres’ depth. Specimens of the type nearly exclusively branched 
by proliferations so extreme as that represented in fig. 499 are rare; they occur 
too in deep water; the great majority of individuals are intermediary between the 
two extremes. The specimens growing in exposed localities in shallow water have 
a firmer texture than those growing in deep water. In specimens growing in 
68° 
Fig. 515. 
