S pectal Morphology and Classification. AUR 
They excrete a thin jelly, in which they often live enclosed as colonies 
(Fig. 388). They are especially distinguished by their apparently 
voluntary movements. 
The SIPHONE consist of a single sac-like, often branched cell, 
the free part that does not root in the ground containing a parietal 
layer of protoplasm with abundance of grains of chlorophyll, [but form- 
ing no nucleus]. They are propagated by oospores, swarmspores, and 
gemmee, as in Vaucheria (Fig. 384, p. 251). To this class belong also 
Botrydium (Fig. 81, p. 55) and Caulerpa (Fig. 380, p. 247). 
The FuUCACE are large brown or olive-coloured seaweeds, often 
many feet long [as in Sargassum, Fig. 387, p. 255], and of a cartila- 
ginous texture. They are attached to stones [or other Alge] by a 
branched attachment-disc. Their L 
branches, which are often beauti- ‘aN | 
fully dichotomous, all lie in one AN Saha 
plane, or can be reduced to one ai sy 
without violence tothe plant. From ee Nee) 2a 
the dead plant cold fresh water YN 
extracts a leather-brown pigment. 
They very commonly form air-cavi- 
ties in the interior of the tissue [or aN 
occasionally elevated on distinct ee 
stalks, as in the gulf-weed (Fig. 
387)], which swell outwards like 
bladders and serve as swimming- 
bladders [as in the common bladder- 
wrack, Fucus vesiculosus]. They 
are propagated by oospores (Fig. 
389). The oospheres are set free 
by the bursting of the oogonia, and 
are fertilised outside the plant by 
the antherozoids. Some _ species IL. 
are moncecious, bearing both kinds 
of reproductive organs [which are 
contained in male and female cow- ET oe 
ceptacles| on the same plant; others IEG 
are dicecious, one individual pro- ye 
ducing antheridia only, another in- 
aos : FIG. 389.—Fucus vesiculosus; \. ¥ 
dividual oogonia only. _ thallus ; 1 fructification ; v air- 
Nearly allied to the Fucaceze bladder (natural size); II. anther- 
are the LAMINARIE, which re- ozoids (greatly magnified). 
semble stalked leaves (Fig. 390). They are reproduced by rather 
S 
