THE THALLOPHYTES 
that of the egg to form an odspore. The odspore at once develops 
into a new Fucus plant. 
The drug Fucus consists of the dried ‘thallus of Fucus vesiculosus, 
Fucus serratus, Ascophyllum nodosum or Halidrys siliquosa (Fam. 
Fucacez). Fucus has been used in the treat- 
ment of obesity and goiter. 
T 
Cass V.—RHODOPHYCEA, THE RED ALG 
A greatly diversified group comprising the 
majority of marine algz but represented also ¢~-% 
by some fresh-water forms of which Batracho- Seat. 
spermum and Lemaneaareexamples. Themarine Fic. 261.—Fucus 
red alge are gencrally found at or just beyond en 
the low water mark. Their vegetative bodies ,  conceptacle, T, 
vary from simple branching filaments through cellular _ thickness. 
all gradations to forms differentiated into hold- ange aa (After 
fasts and branching stem- and leaf-like struc- van 
tures. It has been observed that many of the higher types are 
composed of numerous filaments which are arranged so closely 
and connected so intimately by protoplasmic processes as to 
superficially resemble the tissues of plants of higher domain. 
Their color may be red, purple, violet, or reddish-brown or even 
green. The red color of most of them is due to the presence of 
phycoerythrin, a red pigment, which is found in the chromatophores 
with, but frequently masking, the chlorophyll. Phycocyanin, a 
blue pigment occurs in the chromatophores of some red algae. 
In most of them several chromatophores occur in each cell. 
These are usually small and oval in shape.. Starch is not formed 
but rather another carbohydrate staining red with iodine. 
Reproduction is asexual by spores or sexual by spermatia 
functioning like sperms and by eggs. The spores and gametes 
are devoid of cilia. 
SuB-cLAss FLoRIDE#.—To this group belong plants which 
consist of branching filaments or filaments closely bound by an 
intercellular substance and plasmodesma into dichotomously 
branched, cylindrical or ribbon like thalli. Some of them have 
their bodies composed of cells all alike while others show differ- 
entiation into an outer chlorenchymatous and an inner conduc- 
