OUR MARINE ALG.E. 
37 
OUR MARINE ALG^. 
By Rev. Henry Boyden, B.A. 
{Continued from page 6.) 
We now come to the fructification of our Marine Algas; 
their reproductive organs form a difficult subject, into which I 
have as yet neither the learning nor the appliances to enter 
with any degree of satisfaction. The organs of reproduction 
are called spores, tetraspores, antheridia, and zoospores. It 
is supposed that spores are formed by certain cells which have 
the power of attracting to themselves the contents of adjacent 
cells; and that the fertilising influence is imparted to the 
sporangium at an early stage of its growth, and not to each 
individual spore. Spores are formed in a capsule, or cerami- 
dium, which is an ovate conceptacle pierced by a terminal 
pore containing a tuft of spores rising from the base of the 
conceptacle. The capsule is external, and it is a mode of 
fructification for which the Polysiphonias are conspicuous. 
Spores are also embedded among sporiferous filaments called 
paraphyses. They are found also embedded in soft, pulpy 
berries, which are either simple or variously lobed and 
clustered on the sides of the branches, at one time enclosed, 
at another surrounded by an involucre. These may he seen 
on specimens of the Ceramiums. In other cases the masses 
of spores are found attached, not to the outer surface but to 
the inner, the fronds consisting of a thin membrane rolled 
round. 
Another kind of fruit consists of tetraspores, so called 
because on maturity they break up into four sporules, though 
often into three and sometimes six. The division is various, 
for there is the cruciate, the tripartite, and the zonate. 
It is thought that the spores are true spores fertilised by 
means of an antheridium, while the tetraspores, totally 
distinct, are mere gemmules or buds of the simplest structure, 
which are cast off by the parent plant, carrying with them 
sufficient vitality to become the nucleus of fresh individuals. 
“Each tetraspore consists of a dark-coloured mass of endo- 
elirome enveloped in a transparent membranous sac, and 
marked by the lines of division ” as described. The tetra¬ 
spores are variously placed, some scattered singly, others 
gathered into sori or clusters, others on branclilets, some in 
external warts, nematliecia; others in pod-like receptacles, 
the sticliidia; and their position forms a mark of the different 
genera. 
