Tricotyls as Half Races and Intermediate Races. 353. 
rangement of the leaves in the exhibition of trimerous 
whorls on the stems in the later life of the plant. I paid 
great attention to this point at the beginning of my ex- 
periments when I visited the great nurseries at Erfurt. 
Here the ternary individuals of Antirrhinum majiis in 
the fields impressed me greatly. They were not con- 
sidered by the gardeners as worth any attention, but they 
formed the foundation for my first tricotylous inter- 
mediate race. 
The difference between tricotylous half and inter- 
mediate races lies in their percentage composition and 
not in the visible characters of the individuals. Neither 
the number nor the cleavage of the cotyledons on a single 
individual is decisive. As a rule tricotylous specimens 
of both races tend to produce a richer harvest of the 
tricotyls than the atavists of the same race; but expe- 
rience shows that the difference is only a small one ; and, 
further, that tricotyls, even those of a high productive ca- 
pacity, are often surpassed in this respect by some of their 
atavistic brethren. The chief point is, however, that both 
the half race and the intermediate race are composed of 
both types of individuals ; in the former the tricotyls are 
rare, whereas in the latter, under normal circumstances, 
both forms appear in about equal numbers. Moreover, 
both races contain all the stages of hemi-tricotyls, and, 
although these are rarer, of hemi-tetracotyls also. 
It is not possible, therefore, to tell from a single plant 
to which race it belongs. Only its ancestry can deter- 
mine this; and if this is unknown, we have to reach the 
decision by means of subsequent breeding. It is an ex- 
treme case of the transgressive variability which was 
discussed in the first volume. 1 The forms composing a 
'Vol. I, Part IT, 25, pp. 430 ff. 
