16 BOTANICAL GAZETTE [you 
centric rings when in open room, i.e., alternate light and darkness, 
but in continuous darkness they were irregularly scattered. Culture — 
no. 35 made concentric rings when in the light, and failed to do so 
TABLE I E | 
Relation of light to growth 4 
Figures express growth in millimeters. The cultures marked ‘“‘alternate’” were 
kept several days in light and several days in dark; L light; D dark. Inoculated 
Dec. 8, 1908. %@ 
DECEMBER 
LIGHT CONDITION 
9 TOs) ix] eo fs | yas | as. | x65) ee ope 
E Tn: light <a; germ | 1 6 |9 | 13 | 16| 17 | 23 | 20 
ple ternate a ee L D|LIL 
Praxeicen light & dark / |germ | x 6 | ro | 12 | 15 | 27 | 23 | 26 
te eae I 6 |9 | 1 | 15 | 17 | 22 | 29 
Ie lhe eos. o | gr. 4 to | 13 | 14 | 16 | 20 
Phyllo-  \ Alternate SEV ErL Ep |p Dys 
Sticta sp.) light & dark o | gr 4 17 | 10 | 13 | 13 | 16 | 18 
In dark........ o | gr. 4°16 |)7 1 10 f 33 | 16-8 
Th hent. 3... 4 ra [1g | 27-125 |-06-}°33 4-49 
Chote: Alternate { fa fe St ae ON RS Si DID D L 
os light & dark 2-4-3 12 | 16 | 20 | 25 | 30 | 37 | 39 
In: dark... :.. m 12.} 141-38 |. 22.) 25 | 321-32 
when moved to darkness. Cultures kept in the open room lay dow 
rudiments of pycnidia mainly during the night, and it is probable that 
light exerts enough inhibiting influence on pycnidial development lo 
give a growth predominance during the day and a fructifying P 
dominance during the night (HEDcEcocx, I. c.*). : 
Alternaria Brassicae (Berk.) Sacc.—With this fungus the end 
each day’s growth, evening, marks the edge of a zone. The zone U 
marked is intensified during the succeeding twenty-four hours 
_color changes. While zones are formed to some extent in continu 
darkness, they are more pronounced in the room condition. 
SUMMARY OF LIGHT RELATION 
Light exerts little or no effect upon lineal growth with these fung i 
It appears to exert an inhibiting influence on pycnidial developmé 
and in some instances is the cause of zonation in colonies. 
