I 
SEXUALITY IN PLANTS. 
373 
other plant or variety. In this manner, too, he would counteract 
that weakness of constitution, the result of continual in-and-in 
breeding, and which is so apparent in many of the higher bred 
flowers and vegetables of the present day, and which leaves them 
an easy prey to disease and parasitic fungi. At any rate, we 
owe to the observation of practical gardeners the establishment 
of the fact that a relatively high temperature is most conducive 
to the formation of stamens in the case of strawberries, a low 
temperature to that of pistils. So again, in the case of vines, 
it has been observed that a high temperature conduces specially 
to the formation of tendrils, a low one to that of fertile flowers. 
It is probable, however, that varying conditions of moisture 
may have as much effect in this way as the mere variation of 
temperature. 
That parasitic fungi should determine the formation of 
stamens seems at first sight sufficiently remarkable. Never- 
theless such is the opinion held by M. CornU; in France, and 
it was independently brought before the notice of the British 
Association at Exeter, by Miss Becker. Moreover, the notion 
receives the assent of the veteran mycologist, the Eev. M. J. 
Berkeley, than whom none more competent to express an opinion 
on such a subject. The facts are as follows : — The common 
Lychnis of our hedges. Lychnis diurna, has unisexual and 
dioecious flowers ; but when affected by a parasitic fungus, the 
flowers, which should be pistillate only, develop stamens also. 
This is attributed by Miss Becker to the fact that the fungus 
( Ustilago antherarum), although able to penetrate the plant, 
can only fructify in the anthers, and consequently it becomes 
the determining cause of the production of the stamens in the 
normally female flower. We have not all the evidence before 
us, on which account we find it difficult to understand how the 
presence of the fungus in the anthers should be taken as a 
proof that they (the anthers) were called into development by the 
fungus. That other flowers on the same plant unaffected with 
fungus should have pistils only and no stamens, is surely not 
to be taken as a proof that parasitic fungi can cause the 
development of stamens. The origin of sexual differences, and 
the power of inducing in animals the appearance of one or 
other at will, have from the oldest times exercised the thoughts 
of philosophers. As we have seen, the solution of the problem 
is not only of the highest interest as a matter of science, but 
also as regards the direct material welfare of mankind. With- 
out intending any disparagement to the devotees of the sister 
science of zoology, we may yet affirm confidently that the 
botanists and gardeners between them have so far advanced 
considerably beyond their confreres in the unravelling of this, 
by no means the least, of the mysteries of life. 
