486 CO-RELATION. 
position .of these cords have also been considered to 
bring about deviations from the rule of alternation, 
but in general the formation of the cords is subsequent 
to that of the growing points or mamelons. 
Adhesions, accompanied by displacements, occa- 
sionally produce similar deviations, the nature of 
which is usually easily detected. 
Co-relation.—The importance of this subject first pro- 
minently brought into notice by Geoffroy St. Hilaire 
gains in force daily. Rarely is a malformation an iso- 
lated 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 recep- 
tacle. Let an ordinarily concave thalamus remain, from 
defective development, flat, and how great the change 
in the appearance of the flower. Let the usually con- 
tracted 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.’ 
Not only is the whole symmetry changed, but the 
physiological operations carried on in the flower un- 
dergo corresponding alterations. 
1 A singular instance of co-relation was shown by Mr. Saunders at 
the Scientific Committee of the Royal Horticultural Society, February 
16th, 1868, in a hyacinth with perfectly green, long, tubular, erect, not 
horizontally spreading flowers. , 
