KARLING: GROWTH AND REPRODUCTION IN CHARA 477 
and at the time of photographing the period of daylight was 
about 13%4 hours. Since the artificial light was not turned on 
until sunset and then turned off at I a. m. there was a constant 
decrease in the period of electric illumination corresponding to 
the increase in daylight period. 
The growth in length of the plants subjected to artificial 
illumination was generally greater and more rapid as noted, 
but etiolation developed as the experiment continued. The 
internodes were considerably longer than those of the control, 
and the leaves were shorter in proportion. By the end of April 
CuHart 1. Showing the temperature variations of the cultures of Chara 
fragilis throughout the period of experiments. 
2022249698301 3 5 7 9 
MARCH APRIL 
the control culture, left to itself, was overrun with filamentous 
algae, and at the end of May the Chara plants had completely 
disintegrated. The two cultures which had been subjected 
to the electric illumination were placed on a north window 
shelf away from the electric light on May 4. The subsequent 
growth of these plants was slow. A few antheridia and oogonia 
appeared on the new growth throughout the summer. FIG. 3, 
PLATE 13, shows three typical plants of Culture A photographed 
June 11. By the end of September one of these cultures was 
dead. Tips 10 cm. long from the remaining culture were trans- 
planted to a pot of fresh sand loam. By November 6 a new 
vegetative growth was beginning, but no antheridia and oogonia 
were visible. 
