188 ALTERATION OF POSITION. 
ceptible. It cannot at present be stated what precise 
circumstances induce the one mass to form mother-cells 
and pollen-grains, and the other to develop an embryo 
sac and germinal vesicles. Position and external cir- 
cumstances may have some indirect effect, and it may, 
perhaps, be significant that in all the imstances of 
polliniferous ovules, the ovular structures have been 
exposed on an open carpel or otherwise, in place of 
being confined within the cavity of a closed ovary, as 
under ordinary circumstances. Hven among Conifers 
the ovuligerous scales are so closely packed that there 
is little or no exposure of the ovules. But, apart from 
all speculative notions as to the relation between the 
structure and functions of the anther and of the ovule 
respectively, and of the possibility or the reverse of 
parthenogenesis, it will clearly be necessary im any 
future alleged occurrence of the latter phenomenon to 
ascertain whether any or all of the apparent ovules are, 
or are not, anthers in disguise. 
Homomorphic flowers of ‘* Composite.’ '—In a large section 
of the Composite there is, as is well known, a distinction 
between the florets of the “disc” and those of the 
“ray, the latter being ligulate, the former tubular. 
In what are erroneously called double flowers in this 
order, e.g. m the Chrysanthemum, Dahlia, &c. &e., the 
florets are all hgulate. This change is sometimes 
classed with peloria, but there is no abnormal regu- 
larity in these cases. On the other hand, were the 
ligulate florets to be all replaced by tubular ones, the 
term peloria would be more strictly applicable. It will 
be remembered that in the sub-order Liguliflore, the 
florets are naturally all ligulate, so that the change 
above mentioned is not in itself a very grave one. 
Heterotaxy affecting the inflorescence Under the head of 
Prolification, Heterogamy, &c., various deviations from 
the normal inflorescence are alluded to. In this place, 
therefore, it is only necessary to mention certain rare 
