RED SEAWEEDS 209 
the substance of the plant body. The plants are col- 
lected, washed and dried and so preserved for human food 
(blanc mange) and especially as a food 
for convalescents. The structure of Cal- y 
lymenia is similar to that of Chondrus. : Bi\ 
327. Among the very commonly col- ¥ f 
lected Red Algae on either coast are speci- 
mens of Plocamium remarkable for the 
beauty of its color and the regularity of  odien23s. 
its branching. 
Laboratory Studies. (a) It is better for the student to 
study the living plants of this phylum at the seashore, but the 
beginner should not fail to make a study of such specimens as 
may be accessible. Specimens for the study of structure should 
be preserved in alcohol or formalin, using sea-water instead of 
fresh water. However, much may be made out by the careful 
examination of dried specimens which may be obtained from 
dealers. Red Seaweeds may often be obtained ‘‘in the rough” 
which can be moistened and then pressed out and dried for 
study. Such material will often yield quite good specimens. 
Good mounted. microscopic specimens may .sometimes be ob- 
tained showing the structure of the plant as well as of the sexual 
and asexual reproductive organs. 
(6) Make careful microscopical examination of Poly- 
siphonia using alcoholic or formalin material. Such mounts 
should be made in sea-water or a 3 per cent. salt solution to 
avoid the swelling of the cell walls. In the course of the study 
the following should be noted: (i) the cellular structure of the 
plant body, (ii) the tetraspores, (iii) the antherids, (iv) the 
oogones (difficult to find), (v) the cystocarps with their spores 
(carpospores). The closely related Dasya may be substituted 
for Polysiphonia. 
(c) Study the tissue of Chondrus. 
(d) Dried specimens of some or all of the following genera, 
mounted.on heavy white paper, or cardboard, should be 
available for macroscopic examination. 
Porphyra, Batrachospermum, Corallina, Grinnellia, Nito- 
phyllum, Polysiphonia, Dasya, Chondrus, Callophyllis, and 
Plocamium. 
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