104 
ANNE M. LUTZ 
either or both sexes, these may be the only two that are capable of 
uniting and producing viable seeds. If the 8+7 combinations unite 
gametes which, together, reproduce the parental characters, the 
plant will, of course, breed true. If they unite other types the plant 
will prove inconstant, notwithstanding the fact that the offspring, like 
the parent, will have 15 chromosomes. 
C. 16-Chromosome Mutants^^ 
I. hata-like Forms 
The first i6-chromosome mutant recognized at Cold Spring Harbor 
or elsewhere, was found in a 1908 culture of 0. Lamarckiana X 0. La- 
marckiana, and the second in a 1910 culture of the same form. Since 
the somatic chromosome number of the 1908 mutant was ascertained 
in the winter of 1 908-1 909 and that of the 1910 plant in the spring of 
191 1, they were not known to be mutants of particular interest at 
the time of their growth and were not photographed. 
While the two were in no sense identical forms, both have been 
properly characterized as lata-like plants. In common with 0. lata 
Nos. 5343 (1908) and 3474 (1910) had crinkled leaves, yellow-green 
foliage, irregularly shaped buds, and were male-sterile. The leaves 
of No. 5343, in all stages of development, were conspicuous because 
of their relatively short and broad leaf-blades and long petioles, but 
the leaves of No. 3474 were very much narrower and more sharply 
pointed than those of 0. Lamarckiana lata. In both cases these dif - 
ferences were very conspicuous in the full-grown rosettes. The true 
lata mutant produced by Lamarckiana is usually much shorter 
than Lamarckiana, but No. 3474 was almost as tall as the parental 
form when full grown, its height being correlated, undoubtedly, with 
the great distance between nodes — one of the conspicuous characters 
of the plant. In proportion to the length of the stem, the branches 
'^^ The discovery of i6-chromosome mutants in Oenothera was announced with the 
following statement in 191^ (Lutz, " Triploid mutants in Oenothera," p. 433): "I 
may anticipate a future report sufficiently to state that I have found many quite 
distinct types of mutants with 15 chromosomes, and some even with 16." No 
further information concerning these mutants was given out at that time and the 
plants were not mentioned again by the writer until referred to in a paper read 
before the Botanical Society of America in December, 191 5, and in the note which 
followed (Lutz, 'i6a). Gates stated in 1915 ("The mutation factor in evolution," 
p. 167) that i6-chromosome forms had been described, but since there appear to be 
no recorded descriptions of such forms antedating the note just mentioned and the 
paper in hand, it is probable that he referred to the mutants reported in 1912. 
