FIFTEEN- AND SIXTEEN-CHROMOSOME OENOTHERA MUTANTS 57 
phasized throughout the report (pp. 390, 416, 418, 420) that all in- 
dividuals having identical somatic characters from seedling to fruiting 
stage invariably have identical somatic chromosome numbers, regardless of 
the parentage or the origin of the plants in question. Owing to the con- 
tradictory nature of the evidence produced by Gates and Lutz relating 
to somatic chromosome number in 0. lata, it was feared that this type 
might be regarded as an exception to the rule.^ It was therefore stated 
(p. 416) that the Cold Spring Harbor studies had established the 
precise somatic chromosome number of 28 latas; that each had been 
found to have 15 chromosomes, "whether mutant, hybrid, offspring 
of mutant lata self-pollinated, or offspring of hybrid lata self-polli- 
nated; whether grown at Amsterdam, Cold Spring Harbor, or the 
New York Botanical Garden; and whether derived from de Vries's 
cultures, from plants descended from plants or seeds from de Vries, 
or from plants of English ancestry, in no wise related to de Vries's 
cultures." 
Later in the same year in which the above announcement was made, 
Gates ('12) stated that he had counted the chromosomes in one lata 
plant and had found the number in this individual to be 15, and added 
(p. 995): "From all the counts thus far made of the chromosomes in 
0. lata it appears that the number 15 occurs at least in most individuals, 
though the counts are perhaps not yet numerous enough to show that 
15 is the number for all individuals, . . ." From a note added at the 
conclusion of this report, it seems that the statement concerning 
0. lata in "Triploid mutants" had not appeared in print or had not 
attracted his notice at the time this communication was sent to 
press. In the note he says that the preparations of 0. lata described 
in his first paper on the subject were re-examined, but that they had 
deteriorated somewhat and he was "unable to determine with cer- 
tainty whether this lata plant contained 14 or 15 chromosomes." 
Since Gates's early statements were clearly based upon a number 
of counts, it seems improbable that the extra chromosome, if present, 
^ One may be led to inquire also whether 14+^-chromosome forms may not be 
regarded as exceptions to the rule. In considering this question it should be borne in 
mind that we do not yet know whether the small member of the chromosome group 
is constant or variable. Should future studies show the latter to be true, we should 
then be called upon to decide whether these 14+^-chromosome forms should be re- 
garded as actual exceptions to the rule, since the small body is, in' all probability, 
not a chromosome, but merely a detached fragment of a whole chromosome, or a 
remnant of a degenerating chromosome. 
