POLLINIFEROUS OVULBES. 187 
of the ovule, while the pollen was formed within the 
nucleus. In no case was any trace of embryo sac 
to be seen. 
The main interest, as Mr. Salter remarks, in these 
cases is physiological; so far as structure alone is con- 
cerned, there does not appear any reason why pollen- 
erains should not be developed in any portion of the 
plant; the mother cells in which the pollen is formed 
not differing, to all outward appearance, from any other 
cells, unless it be in size. 
The fundamental unity of construction in all the 
organs of plants could hardly be better illustrated than 
by these cases; while, in spite of their exceptional 
nature, they must be of great interest physiologically, 
as showing the wide limits of possible variation which 
thus may even involve the sex, “for an ovule to 
develop pollen within its interior,” says Mr. Salter, 
**is equivalent to an ovum in an animal being converted 
into a capsule of spermatozoa. It is a conversion of 
germ into sperm, the most complete violation of indi- 
viduality and unity of sex. * * * * The ‘occurrence 
of an antheroid ovule and a normal ovule on the same 
carpellary leaf realises the simplest and the most abso- 
lute form of hermaphroditism.” 
It must, however, be remarked that the term sub- 
stitution would be preferable to conversion. There is, 
at present, no evidence to show that the germinal 
vesicles were present in these cases; on the other 
hand, it seems most probable that they were not, so 
that the presence of the pollen-cells must be con- 
sidered as simply adventitious. It can hardly be 
that they were, in the first instance, germinal vesicles, 
which, in course of time, became so modified as to 
assume the appearance of pollen-grains. Between the 
nucleus of the ovule and the tubercle of cellular 
tissue constituting the primordial anther, there is little 
or no difference, so that it may be said that, for a time, 
there is no distinction of sex in the nascent flower, but 
as development goes on, the difference becomes per- 
