SEXUALITY IN PLANTS. 
369 
We take it, then, that there is a primordial oneness of sex, as 
Plato long since argued, and in that sense we agree with Dr. 
Spruce. We are constantly meeting in plants with traces of 
this essential unity of sex. We can see it in the development 
of all flowers; we meet with it frequently in the structural 
changes from one sex to the other, and to which we have already 
drawn attention. If we find the same organ hearing, at the 
same time, on one side pollen and on the other side ovules — a 
by no means unusual occurrence — it is difficult to conceive that 
there can he so great an intrinsic difference between the sexes 
as is usually admitted. If we find the pistil producing pollen, 
and the stamens forming ovules — as happens not unfrequently in 
the common stonecrop and in the wallflower — our belief in the 
absolute diversity of the two sexes becomes less implicit. If 
we meet with ovules hearing pollen in their interior, as has now 
been seen in species of passion-flower by Mr. J. A. Salter, and 
by the writer in a rose, our faith in the duality of sex becomes 
well nigh uprooted. In face of such evidence is it not reason- 
able to suppose that as sexual characteristics of any kind are 
themselves secondary in point of development, and individual, 
not specific, so the dual nature of the sexual principle, so con- 
spicuous in the adult organism, is a later development or evo- 
lution from an originally homogeneous unity ? The old tradi- 
tion of the development of Eve from the rib of our forefather 
Adam may not after all he so purely mythical an assertion. 
What hlilton said of the spirits may, if we exclude the notion 
of volition, be properly applied to plants : — 
Spirits, when they please, 
Can either sex assume, or both.” 
It remains now to enquire what are the causes which disturb 
the equilibrium in the first instance, and to ascertain what are 
the special circumstances which favour the development of one 
sex at the expense of the other. 
With reference to the first point, it would appear that although 
very slight causes are sometimes sufficient to deflect the balance, 
yet at others, and those more frequent, much more violent 
changes are powerless to bring about such a result. 
Allusion has been already made to a seedling Papaw, the^ 
produce of American seed developing hermaphrodite flowers 
when grown on the shores of the Mediterranean, and the 
changed conditions have been assumed to be sufficient to 
account for the phenomenon. On the other hand we have 
seen a male plant of the Papaw, cultivated for years in the 
Oxford Botanic Grarden, suddenly produce bisexual flowers 
without obvious change of condition ; and numerous parallel 
changes are familiar to all observers. Sometimes in these cases 
VOL. XII. — NO. XLIX. B B 
