Development of Laminaria hulbosa , L amour. 5 r 
a branching could be brought about, and that is by the fusion of several plants 
which have germinated side by side. Reinke, in his paper on Fucus vesiculosus ', 
suggests this explanation for those cases where several plants of about equal size 
spring from the middle of one disc of attachment. The tissues of these Algae would 
certainly lend themselves to such a fusion, because of their exceedingly well marked 
‘gliding growth.’ In support of his suggestion Reinke refers to a figure of 
Kutzing’s 2 , where an individual of Fucus vesiculosus and one of F. serratus spring 
from the same disc. If this is the case with the several-stalked Laminaria 
bulbosa , the fusion must have taken place in the young plant as far as the point 
where the ridge would arise. 
The lower part of the flat portion just above the twist 
soon becomes altered. The edges appear to grow in length 
far more rapidly than the median part. The result is that 
they are very much convoluted, while the median portion 
is perfectly flat. This is well seen in Fig. 23, which is copied 
from that given in Harvey’s Phycologia Britannica. The 
curious foldings of the stalk have long been noticeable 
enough to earn for the plant the popular name of ‘ Sea 
furbelows.’ It was on these furbelows that Sowerby first 
detected the sporangia. 
Thus the stalk during development becomes differentiated 
into the following parts. 1. The primary fixing organ below 
the ridge. 2. The ridge itself with the organ developed 
from it. 3. The flat, twisted portion immediately above 
the ridge. 4. The part with convoluted edges. 5. The 
upper flat portion, which passes somewhat suddenly into 
the widely expanded, much divided frond. 
To describe the shape of the lamina in detail does not 
come within the scope of this paper ; and, even if suitable 
material were procurable, such a description would not be 
of much value ; for the lamina varies greatly, and, accord- 
ing to Agardh, ‘from the form of the frond no distinct 
characters are to be obtained 3 .’ The lamina is at first 
entire (Fig. 1), and contains many small pits with filaments 
protruding. These are the ‘flowers’ of Reaumur; and the 
filaments, according to Greville, are merely the free ends 
of the cell-rows at the mouth of the pit. The subsequent 
1 Pringsh. Jahrb. x. p. 318. 2 Phycol. general, x. t. 11. 
3 Sp. Alg. i. 134. 
E 2 
