174 PLANT LIFE 
This species of Lychnis is a dicecious plant. 
That is to say, the flowers of some plants are 
exclusively female whilst the rest are ex- 
clusively male. The unisexual character is 
produced by the abortion of the pistil in the 
flowers of the male, and of the stamens in 
those of the female plants. The fungus only 
reaches maturity and produces its violet 
powdery spores in the stamens. So far as 
the male plants are concerned there is no 
difficulty, but with the female flowers it is 
otherwise. What the fungus does when it 
attacks the latter is to stimulate the plant to 
produce stamens exactly like those of a male 
flower. The mycelium grows sparsely in 
them until the pollen sacs are approaching 
maturity, then it suddenly breaks out into 
virulence and destroys the pollen-producing 
tissues, filling up the space with its own spores. 
Nor does the influence of this remarkable 
parasite stop here, for the pistil is arrested 
at an early stage of its development and in 
certain other structural characters the flower 
closely approximates to that characteristic 
of a male plant—so closely indeed that very 
careful experiments were needed to clear up 
the matter. 
It is not known what the substance formed 
by the fungus, and responsible for the change, 
really is. All attempts to imitate its action, 
and to produce a similar result artificially 
have so far proved unsuccessful. 
The somewhat common “ witches’-brooms”’ 
