Helianthus Annuus Syncotyleus. 473 
If all the seeds of a single head are planted out in 
groups according to their degree of syncotyly, very little 
differences will be seen in the results. Atavists and seed- 
lings, in which the fusion extends less than half way up, 
give a progeny the value of which is, on the average, 
somewhat lo\ver, but only if we fix our attention on the 
mean values, and not if we compare the single individ- 
uals. Many an atavist or hemi-syncotyl has a higher value 
than most of the average syncotyls, and amongst these 
latter, the question whether the fusion is so complete 
that the apex of the double leaf exhibits no invagination, 
has no effect on the hereditary values of its offspring, so 
far as I have been able to determine. In the same way 
the disturbances in the disposition of the leaves, which 
so often follow on syncotyly, are of no value as selective 
characters ( 9) ; but it is not necessary to describe the 
experiments which prove this point. 
Hemi-syncotylous seedlings are always rarer, and 
often much rarer than the true syncotyls ; amongst these 
latter on the other hand, the highest degrees of symphysis 
are more abundant than the lower ones, which have an 
obvious invagination of the apex. I have often recorded 
separately the various degrees of syncotyly in my seed- 
lings. In this way figures are obtained which give curves 
with two peaks, such as have been found for other anom- 
alies, especially for fasciation. 1 The atavists constitute 
one peak and the most complete syncotyls the other. From 
the former the curve drops rapidly to mount again grad- 
ually with the increasing degrees of symphysis ; whilst 
on the other side of the apex of the syncotyls there is 
another rapid drop to the very rare cases of amphicotyly, 
* Sur les courbes galtoniennes des monstruosites, Bull. Scientif. 
de la France et de la Belgique. Public par A. GIARD, Vol. XXVII, 
p. 396, April, 1896. See especially the curve on page 397. 
