236 
of these intermediates or periclinal 
chimeras is shown in The Journal of 
Heredity, Vol. 5, No. 12, and an excel- 
lent discussion of how such chimeras 
are produced is there given. 
Similar study of Cytitsus Adami and 
the Crataegus-Mespilus so-called graft- 
hybrids showed that they are also 
periclinal chimeras with one or more 
cell-layers of one species covering a 
body of cells of the other species. 
INTERACTION OF DIFFERENT KINDS OF 
CELLS 
The rather intimate association of 
the cells of two different species in the 
same stem, leaf, flower, and fruit is 
especially interesting in view of the 
mutual interactions, mechanical and 
physiological, that may occur. The 
evidence indicates that the two kinds 
of cells remain independent in respect 
to their own hereditary characteristics, 
but in the periclinal chimera they 
interact producing organs that are 
intermediate in character. Slight dif- 
ferences in the arrangement of the 
same two kinds of cells also produces 
vegetative and floral s ructures and 
fruits that are quite different in 
appearance. 
While the investigations indicate 
that the supposed graft-hybrids are 
in nature only periclinal chimeras, the 
production of true graft-hybrid through 
a fusion of vegetative cells is still to 
be considered possible. In fact Dr. 
Winkler has presented evidence that 
this is the case in one adventitious 
branch that arose from a decapitated 
graft between the tomato and the 
nightshade. 
The production of sectoral and peri- 
clinal chimeras by experimenal means 
readily shows how such branches can 
arise incidentally on plants grafted by 
the ordinary methods. New and 
adventitious buds may arise from the 
region of union between stock and 
scion, especially if the upper part of 
the scion dies. If such a bud arises 
over the line of contact it may develop 
as a chimera. Dr. Winkler’s studies 
show that sectoral associations develop 
more frequently than do the periclinal. 
The Journal of Heredity 
CHIMERAS THROUGH BUD SPORTING 
It should be noted that intra-varietal 
sectoral and periclinal chimeras fre- 
quently arise through bud _ sporting. 
Such partial bud sports have been 
described frequently in the pages of 
this jouril, especially for such 
conspicuous cases as the loss of green 
color which is carried on into various 
new branches. 
Some of the albomarginate types of 
variegated plants (of Pelargonium for 
example) are clearly periclinal associa- 
tions of green and white cells all of 
which belong to the particular variety. 
In the original sport, most probably, a 
single cell lost the ability to produce the 
green pigment and this cell was so 
placed in the growing point that its 
multiplication by division gave one or 
more layers of white cells. Once 
established the relative position of the 
white and the green cells was main- 
tained rather uniformly in the subse- 
quent development of branches. 
It is also to be noted that, in many 
sorts of variegated plants, though the 
pattern strongly simulates a chimeral 
arrangement, it is really due to physio- 
logical conditions affecting develop- 
ment of color in the leaf as a whole. 
In these the colored and _ colorless 
areas often cut across cell layers or 
histogens. Much remains to be 
learned regarding the development of 
such local areas of infectious chlorosis, 
as well as the development of various 
patterns of anthocyania coloration in 
flowers and foliage. 
PROBABLE ORIGIN OF THIS CHIMERA 
Mr. Whitney’s tree bearing Russet 
and King fruits is evidently a chimera 
that has grown from a bud that arose 
on the line of contact between scion 
and stock, and is hence to be considered 
as a graft-chimera. Presumably a 
scion of King was grafted to the root 
of a seedling of the Russet in the 
method of ordinary nursery practice. 
At any rate the tree is clearly an inter- 
varietal chimera: some branches are 
composed of sectors of tissue of two 
varieties; lateral branches arising from 
