that of the growing points or mamelons.

Adhesions, accompanied by displacements, occasionally produce similar
deviations, the nature of which is usually easily detected.

=Co-relation.=--The importance of this subject first prominently brought
into notice by Geoffroy St. Hilaire gains in force daily. Rarely is a
malformation an isolated phenomenon, almost always it is associated,
from the operations of cause or effect, with some others. Instances of
this co-relation have been cited in the preceding pages, and many more
might have been mentioned, had the consideration of the relationship
between form and function formed part of the plan of this volume. A
change in itself slight, often acquires importance from its association
with other alterations. This is particularly well seen in the case of
the receptacle. Let an ordinarily concave thalamus remain, from
defective development, flat, and how great the change in the appearance
of the flower. Let the usually contracted receptacle be lengthened, and
the whole aspect of the flowers so affected is altered to such an extent
that, were their history not known, botanists would have no hesitation
in assigning them to widely separate groups in their schemes of
classification. Peloria, too, of either form, affords excellent
illustrations of the co-existence of one changed condition with another.
Not only is the form of one set of organs altered, but the number, the
relative proportion, and the direction of the other organs of the flower
are altered likewise.[562] Not only is the whole symmetry changed, but
the physiological operations carried on in the flower undergo
corresponding alterations.

There are certain co-relations which do not appear to have hitherto
attracted the attention they merit; such, for instance, is that which
exists between the particular period at which an organ is developed and
its position and form. In normal morphology this has, to some extent,
been worked out, as in the case of definite and indefinite, centrifugal
and centripetal inflorescences, and in the definite or indefinite
formation of shoots, &c.

Other instances may be cited in the frequent co-existence of regular
flowers and definite inflorescence, the terminal position of many
peloriated flowers, the relationship between indefinite inflorescence
and prolongation of the axis, &c.

Again, the simultaneous evolution of the parts of the flower and their
consequent verticillate arrangement, a