246 
PHARMACEUTICAL BOTANY 
gains an entrance, after which its nucleus fuses with that of the egg 
to form an oospore. The oospore at once develops into a new Fucus 
plant. 
Class III.— Rhodophyce^e, the Red Alg,e 
A greatly diversified group comprising the majority of .marine algae 
but represented also by some fresh-water forms. The marine red 
algae are generally found at or just beyond the low water mark. 
Their vegetative bodies vary from simple branching filaments 
through all gradations to forms differentiated into branching stems, 
holdfasts and leaves. 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 resemble the tissues of plants higher up. Their color may be 
red, purple, violet, or reddish-brown or even green and is due to the 
presence of phycoerythrin, a red pigment, which is found in the 
chromatophores with but frequently masking the chlorophyll. 
Chondrus crispus and Gigartina mamillosa yield the official drug 
Cbondrus, Irish Moss or Carragheen. Both are purplish-red in 
color. Each consists of a dichotomousl/’ branched thallus the 
lower portion of which is differentiated as a stipe or stalk; the basal 
portion of which, called the holdfast, clings to the rock. The upper 
part is several times forked and its terminal segments appear notched 
or bilobed. Scattered here and there over the segments of the 
thallus will be noted sporangia which, when mature, contain tetra- 
spores. In Chondrus crispus the sporangia are elliptical and em¬ 
bedded in the thallus near its surface, whereas in Gigartina they are 
ovate and project outward from the surface of the segments. Upon 
the ripening of these structures the spores are discharged into the 
sea water. These sooner or later germinate into new Chondrus or 
Gogartina organisms. 
The dried mucilaginous substance extracted from Gracilaria 
lichenoides , Gelidium and Gloiopeltis and other species of red algae 
growing in the sea along the eastern coast of Asia constitutes the 
drug Agar, a most valuable ingredient in culture media as well as 
a laxative. 
