520 
ANNE M. LUTZ 
forms never have duplicate vegetative characters; would the same be 
true of 14-, 14+^- and 14+2-chromosome plants? 
5. Chromosomal Individuality 
Gates found that the chromosomes of Oenothera present no constant 
differences in size and shape, and, with the exception of the small 
chromosome in the 14+^-chromosome mutants, the observations of the 
writer are in full accord with those of Gates. The small member of 
the 14+^-chromosome group, however, presents a very conspicuous 
exception, for we have seen that it may he recognized constantly hy its 
shape and hy its diminutive size. It furnishes very strong evidence in 
support of the theory of chromosomal individuality. 
6. O. ruhrinervis 
While de Vries has shown that ruhrinervis is one of the common 
mutant types produced by 0. Lamarckiana, I have found no mutant 
in the Long Island or Indiana cultures of 0. Lamarckiana X 0. 
Lamarckiana which could be said to duplicate the type which de Vries 
has figured and described ('09, Vol. I, figs. 49 and 67). However, a 14- 
chromosome mutant (type 3514, see page 508) which seems to be a modi- 
fied form of 0. ruhrinervis de Vries, is very common. It differs from 
the Amsterdam plant chiefly in height and branching habits, attaining 
the full height of O. Lamarckiana, and, like the latter form, giving off 
a number of long rosette branches. It is shown as an early flowering 
plant in text figure 6 and as a late flowering plant in text figure 7. Mac- 
Dougal's excellent photograph ('05, PI. XXI) of ''O. ruhrinervis'' at the 
New York Botanical Garden portrays the branching habits of the Cold 
Spring Harbor mutant very clearly. Since it appears to duplicate the 
vegetative characters of the C.S.H. plant, it is probable that it also 
had 14 chromosomes. In response to an inquiry concerning the 
history of this individual. Dr. MacDougal stated that the plant photo- 
graphed had been grown directly from seeds received from Professor 
de Vries. 
Type 3514 produced quadrangular buds with deep red sepals; the 
flowers also were deeper yellow than Lamarckiana flowers. Large 
quantities of seemingly good pollen were exposed, consisting of 3-lobed 
grains, and seeds from these plants, selfed, were obtained without 
difficulty. 
