230 BOTANICAL GAZETTE [MARCH 
In the first case, as in the typical Leptosporangiatae, a small 
papilla is formed and cut off from the body cell by a wall. This 
papilla elongates to form the first rhizoid. It contains no chloro- 
plasts. Occasionally two such papillae are formed before the 
division of the prothallial cell (figs. 54, 55). Following the forma- 
tion of the first rhizoid, the body cell increases in size, the oil 
globules disappear, and the chloroplasts increase in size and number. 
The second division of the spore produces a new prothallial cell 
containing chloroplasts. ; 
In the second case, the first division may produce two prothallial 
cells similar in size, and both containing chloroplasts. The basal 
cell of such a group may later produce a rhizoid. From the 
examination of many germinating spores and young prothallia, 
it seems quite as common for the spore to undergo one or two divi- 
sions before the formation of a rhizoid as for the rhizoid to result 
from the first cell division. Numerous specimens similar to fig. 52; 
but without a rhizoid, have been seen. As germination proceeds, 
the perinium is distended but is not cast off; it may usually be 
found attached to the oldest cell of mature prothallia (figs. 14, 15)- 
As has been stated, immediately after the rupture of the walls, 
light green plastids appear in the exposed portion of the cell (figs. 
51, 54). With the further growth of the spore and the formation 
of new cells, these chloroplasts become larger and increase rapidly 
in number. Throughout the life of the prothallium the chloro- 
plasts retain a distinct yellow tinge, imparting a characteristic 
color to the plant. They at all times show a quick reaction to 
intense light, crowding close to the vertical cell walls after a few 
minutes of brilliant illumination. The oil globules persist for a 
short time only, and may not be seen after the first division of the 
prothallial cell. 
Early development of the prothallia 
As was stated above, the first division of the cell may produce 
two similar cells, or may cut off a small cell which develops into 4 
rhizoid. If the first division produces a rhizoid, the second division 
produces two cells similar in form and containing chloroplasts. 
Later divisions of the distal cell may occur in either a transvers® 
