202 BOTANICAL GAZETTE [ SEPTEMBER 
mentation, and the cultures to which grape sugar was supplied 
formed buds after two days, both in light and darkness, but in 
greater abundance in the light cultures. With further growth 
in the dark, the buds grew to produce shoots, two, three, and in 
one case five millimeters in length. 
Experiments were performed with several of the species 
which produced protonemata the most readily, to see what 
effect KNO, would have upon the regeneration and manner of 
growth. Barbula muralis and Phascum cuspidatum \eaves were 
grown in I per cent. KNO, without any apparent retardation or 
change in the manner of growth. Bryum capillare leaves pro- 
duced protonemata, but there was a marked retardation of growth 
and the filaments did not reach any considerable size. In 2 
per cent. KNO, Barbula muralis still produced a vigorous growth 
without any marked retardation. The cells were, however, gen- 
erally shorter, and the branching more aggregated. Bryum capil- 
lare and Phascum cuspidatum produced no growth whatever. In 
3 percent. KNO, Barbula muralis produced a slight growth, but 
the filaments did not reach any considerable length. 
A series of experiments was also carried out in order to 
determine the temperature at which protonema formation would 
occur. For these experiments Barbula muralis, Bryum capillare, 
and Phascum cuspidatum were used, with the results given in the 
following table: 
19-21° 24° 27 29.5 32° 36° 
Barbola Wordlig: oo oe x Te UL Bg ee ee” 
Phascum cuspidatum...............|- >< a x< x< x< 
Bryom capillare. >.< ..<..65 ck x< x< ~x< 
pe er pe 
Barbula and Phascum produced protonemata with as great 
vigor at 32° C. as at I9-21°, the temperature of the ordinary 
experiments; but at 36° no growth resulted. At 29.5° the 
Bryum leaves produced no growth but were not killed, since 
when exposed to the ordinary temperature, protonemata were 
