STUDIES IN TERATOLOGICAL PHENOMENA 
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peculiarity to a more marked degree than any other one of the 15 
anomalous plants which appeared in a family of 50 F2 segregates from 
a cross between N. langsdorffii X N. alata. In fact, this hybrid 
family was derived from the same grandparental cross as that in 
which the pistilloid mutant occurred. Instead of a bud mutation 
occurring shortly after fertilization, as was probably the case with 
the homozygous pistilloid character (-2-1 A), this catacoroUa mutant 
(-4- 1 A) must have originally arisen as a change in the gametes of 
one or the other of the grandparental types or in the cells concerned 
in their ontogenesis, if we are to interpret the succeeding experimentally 
obtained results in accordance with our general knowledge of heredity. 
In the F2 generation grown from guarded Fi seed from a cross between 
two normal individuals occurred a segregation of 15 anomalous and 
35 normal plants, making a ratio of 7 normal to 3 abnormal or 2.33 : i. 
Supposedly the abnormals would have all bred true, for the one plant 
(-4- 1 A) which was selfed produced 20 progeny all of which faithfully 
repeated the parental peculiarities in respect to catacorolla, habits of 
growth, character of foliage, size and color of flowers, and color of 
pollen. It is not supposed that only one "altered" egg cell or pollen 
grain was necessarily produced in attempting to explain the place in 
ontogeny at which this mutation arose. Possibly many were formed 
as the result of a prematuration mutation, but if such were the case, 
and if they united with unaltered gametes, the resulting seeds possibly 
were not planted, or if planted, only one Fi plant of this sort chanced 
to be included in those selfed for further propagative purposes. 
Catacorolla in this race is typical of the anornaly as it appears in 
other plant species. Petalloid segments are produced outside the 
ordinary corolla, and partially adhere to it, these segments having 
colored outer and plain green inner surfaces. In other words, the 
normal corolla appears to have been separated at some time during 
its ontogeny into five segments. Later when these fused to produce 
the normal gamopetalous Nicotiana flower, the union appears not to 
have taken place through the careful growing together of the edges of 
each segment, but on the contrary, to have been brought about in such 
a manner as to leave a seam like that made by a tailor. At the 
point of union of two segments, there is a slight waste of material, and 
it is this which is reflexed back in the mature flower and gives the 
catacorolla effect. The segment then is really a piece of left-over petal. 
In some flowers, the petaloid segments are not united with the normal 
