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ANNE M. LUTZ 
(which are the same as those of mutant 0. Lamarckiana lata), in the 
second, are transferred to the offspring through the egg cells, and 
not through the pollen; that the pollen, in each case, behaves precisely 
as the pollen of pure Lamarckiana (pp. 257, 258, 262, 272, 273, 323). 
At the time of the publication of **Gruppenweise Artbildung", O.lata 
was popularly supposed to be the only 15-chromosome mutant pro- 
duced by O. Lamarckiana or other forms, hence de Vries has discussed 
these very important results without reference to the chromosome 
numbers of the plants in question. However, since a number of forms 
are now known to have 15 chromosomes, their behavior may be 
further considered in the light of this fact. 
Bartlett ('150^, p. 103), discussing the behavior of selfed 0. lata 
and O. stenomeres mut. lasiopetala, concludes, in agreement with de 
Vries, that "it appears that the good pollen grains of Oe. lata are genet- 
ically the same as those of Oe. Lamarckiana, and do not carry the 
/a/a-characters." "Thus," he states, "it appears that there is a class 
of mutations of which the eggs are of two kinds; one kind carries the 
characters of the parent species, the other kind the characters of the 
mutation. The pollen grains, however, appear to be of one kind only, 
and to carry the characters of the parent species." He says "we 
must assume that the male 8-gametes are eliminated" and asks if 
it is not possible "that the male gametes which carry the characters 
of the mutation are eliminated because of some physiological defect?" 
"Oe. lata,'' he states, "produces two classes of gametes, with 8 and 
7 chromosomes, respectively. If two 7-gametes fuse, we have Oe. 
Lamarckiana; if a 7-gamete (presumably male) fuses with an 8-gamete 
(presumably always female) we have Oe. lata.'' We shall see that 
the evidence indicates such are the usual, though not the invariable, 
results. 
MacDougal ('07) obtained 94 offspring from selfed 0. lata which 
were identified as follows: 10 0. lata, 80 0. Lamarckiana, i 0. albida 
and 3 0. oblonga. Albida has 15 chromosomes and oblonga 14 or 15. 
De Vries ('13, p. 256) obtained 442 offspring from a hybrid lata, 
selfed, 33 percent of which were 0. lata and 4 percent mutants. The 
remainder were, doubtless, 0. Lamarckiana. It is probable that several 
types of 1 5-, and one or more 14-chromosome forms were included 
among these 17 or 18 mutants. 
In 1908 3 mutant lata offspring of 0. Lamarckiana were selfed at 
Cold Spring Harbor. A total of 360 seeds were obtained and these 
