in the ordinary plants. In full-grown plants collected in summer, the fan-shaped 
frond from the foregoing year is fully preserved even when its growth has quite 
ceased (fig. 479), while the flat portion of the foregoing generation is often decayed; 
only a narrow strip connecting the base of the new shoot with the eylindrical part 
of the foregoing is kept and 
strengthened by secondary corti- 
cal layers. The named 3 (or 4) 
generations of shoots undoubt- 
edly represent an equal number 
of years, and it must there- 
fore be supposed that the up- 
right shoots normally reach an 
age of at least three years. 
In the plant represented in fig. 
488, gathered in April 1906, the 
first generation is represented 
by the short stem having a 
nearly horizontal direction, the 
second reaches the middle of 
the picture. The next generation 
(of 1905) is represented by two 
long shoots bearing cystocarps 
on the margin; the lowermost 
portions of these shoots, covered 
with Membranipora pilosa, were 
probably produced already in 
1904. On the margins of these 
shoots a number of narrow 
proliferations are seen; it is 
however doubtful whether they 
I 
would have been able to pro- 
duce new fan-shaped segments. Red a. 
Phyllophora membranifolia. Store Bell, At Kloverhage south of Nyborg, 
When more than three genera- October. Photo, ‘/; n.s. 
tions of shoots are produced, 
a greater total length of the plant is scarcely obtained; the new shoots do not 
usually overreach those of the third generation. New shoots may, however, arise from 
older portions of the upright shoots and from the basal disc, and the plants may 
thus become several years old. 
The length of the shoots produced in a year is rather variable, varying from 
a few to 10 cm, and there seem to be no great differences between plants from the 
different waters in this respect. Only in the true Baltic Sea is it less, scarcely 
exceeding 5 cm, and at Bornholm 3.5 cm. On the other hand, the total length of 
66* 
