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F. McAllister 
color reaction, from the brilliant red of the pyrenoid bodies to the 
blue of the starch grains. There is no change in the shape of the 
bodies during this change in color though there may be a very slight 
increase in the size of the grains during the transition (figure 8) which is 
of course to be expected. fThere can be no doubt that the red-staining 
pyrenoid bodies become transformed directly into starch grains 
without any change in their form. After this change in the chemical 
composition of the bodies there is a gradual increase in the size of the 
starch grain until the mature grain results. During this increase 
in size the grain has moved outward and when it has reached the 
periphery its growth ceases and it slowly disappears. 
The chloroplasts of the sporophyte, in the vegetative cells not 
shielded by the sheath of the gametophyte, do not differ in structure 
from those of the gametophyte, though they average considerably 
smaller in size. The smaller chloroplasts of the gametophyte could 
not be distinguished in any way from the larger sporophytic chloro- 
plasts (figures 6 and 17). 
No pyrenoids however are recognizable in the plastids of the cells 
of the foot, nor in the embryonic assimilative tissue of the sporophyte 
immediately above the foot, neither in the cells of the columella nor 
in the cells of the epidermis. The plastids of these cells differ also in 
shape, being ovoid or irregularly elongated rather than disc-shaped. 
In many of the chloroplasts of the cells of the region of intercalary 
growth large vacuoles are to be seen, while in the plastids of the spores 
no protoplasmic contents are to be recognized, the plastids having 
become, as Davis says, "storage vesicles of starch." These cells 
lacking pyrenoids nearly all have some starch present within them, 
varying from a single grain in the youngest archesporial cells to many 
grains in the mother cells and spores. 
All of the cells of the ''archesporium" contain single minute 
chloroplasts which are in many cases difficult to distinguish from the 
granular cytoplasmic cell contents (figure 9). They contain a few 
starch grains, but as stated above, no pyrenoid or other conspicuous 
bodies are to be identified. The ground substance of the chloroplast 
stains very slightly, appearing to have almost no granular contents. 
Later as these cells enlarge to form the spore mother cells, the plastids 
also enlarge and minute, elongated or flattened bodies (figure 10), are 
clearly to be seen scattered throughout the chloroplast. There is no 
doubt that if the "Anlagen" of these bodies were present in the 
