480 KARLING: GROWTH AND REPRODUCTION IN CHARA 
When the refrigeration and electric illumination were dis- 
‘continued the plants began to grow rapidly, and by the middle 
of June the plants were 18 cm. long, with abundant antheridia 
and oogonia. | 
SERIES D 
Op AO TRE ONG sg xv Feces be bh a RA Re erie ee te March 26 
Eecoerl co SOUL WiNGOWs oo ae ee ce es vive ss March 26-—April 8 
Gown in south window. under two hours electric illumination in addi- 
tiie Fey AU ee ee eo re a ee a ee wee April 8-May 7 
Grown in south window with only daylight illumination..May 7—Nov. 6 
Culture D consisted of three jars of about 500 plants collected 
at the same time as those of Cultures B and C. They were kept 
alongside of Culture B in a south window in the laboratory and 
had the same temperature and light conditions up to April 8. 
On this date two of the jars were placed under electric illumina- 
tion each night until 8:30 p. m., while the third jar was kept as 
a control. Antheridia and oogonia appeared on April 17, nine 
days after the experiment was begun. No reproductive organs 
were formed in the control culture. Fic. 1, PLATE 12 shows the 
extent of fruiting . contrast to that attained by Culture B in 
Fic. 1, B, PLATE | 
The RET condi and length of day for the period 
of this culture were the same as for Culture B. The vegetative 
growth of the plants was rapid and vigorous throughout. By 
the middle of June the plants were about 55 cm. long and of a 
deep green color. The internodes were longer than those of 
plants growing in nature. No etiolation was evident. 
ulture D continued in a healthy growing condition through- 
out the summer and fall, but fruited only sparingly. The plants 
were approximately .75 meter long by September 12. On that 
date one of the cultures was pruned, and about fifty tips 10 cm. 
long were transplanted to a new jar with fresh soil, thus making 
four cultures in all. The transplanted tips as well as the pruned 
plants immediately began to grow. The other jars also showed 
vigorous growth. By October 19 the new growth in all the 
cultures was about I5 cm., and by November 6 most of the 
plants had abundant antheridia and oogonia. 
SERIES E 
Collected from: park pond 3.<. coc. os is es March 26 
G 
rown in.south wihdOW... 1220.5; 2 ..March 26—April 15. 
Grown in photographic dark room under electric illumination: April 15-May 7 
Grown in east WINdOW . aoe pesos ks ee May 7-Nov. 6 
