SCIENCE IN THE PLANT WORLD 
wood at night is caused by emanations of light 
from Fungus growing in the cavities. A sim- 
iliar organism called Luminous Peridineas 
(sometimes classed as an animal) is responsible 
for the phosphorescence of the ocean and the 
night lights of many flowers. 
About three hundred species of Bacteria and 
fifteen species of Fungus are recognized to be 
luminous. The dead leaves of the tropical 
Banibusa, Nephelium and Aglaia often glow at 
night with the light of these tiny creatures. Or- 
dinary dead Oak and Beech leaves are lumin- 
ous, sometimes shining in spots, but frequently 
glowing throughout with a soft, white, steady 
light. These miniature incandescent lights 
often shine for days, weeks and months, and 
with abundant nutriment at hand, sometimes for 
years. The light is slight in intensity, but uni- 
formly steady and white, green or blue-green 
in colour. It is strong enough to enable the 
plants on which the Fungus ‘grows to photo- 
graph themselves by long exposure to sensitized 
plates. The fungus light has also been used to 
influence the heliotropic movements of plant 
seedlings. In fact, a colony of Fungus has 
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