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ANNE M. LUTZ 
the male gamete, was produced. If the fertihzation combination 
(such as 9 lo + 0^12, or vice versa) resulted in 22-chromosome seeds 
capable of germinating, or if, regardless of the chromosomal contents 
of the gametes of both sexes, of the chromosomal combinations which 
resulted from fertilization, only 22-chromosome seeds were capable of 
germinating, it is clear that a 22-chromosome hybrid might breed true. 
On the other hand, if functional male gametes of two or more types 
(such as 10- and 12-chromosome cells) and a female gamete of a single 
type (say lo-chromosome cells), or vice versa, were produced, and if a 
single type of cell of one sex were capable of uniting with two or more 
types of cells of the opposite sex and of producing seeds capable of 
germinating, it is quite clear that the 22-chromosome hybrid would 
not breed true. 
If enough good pollen were produced by i6-chromosome mutant 
offspring of selfed 0. lata, 0. Lamarckiana, or of 0. lata X 0. Lamarc- 
kiana, to self them, one might expect them to prove less stable than 
14-chromosome forms resulting from 7+7 unions, since they would 
contain two extra chromosomes, whether derived from 8+8, or 
9+7 unions. It is quite possible, of course, that a germ-cell com- 
bination would be formed which would enable the mutant to breed 
true, such as 9 and cf 8, 9 7 and 9 or 99 and 7, but no evi- 
dence has been produced to assure us that such would occur. It would 
not be at all surprising to find that i6-chromosome forms derived 
from 8+8 unions produce only 8-, or 7- and 9-chromosome female 
gametes, and, in case viable pollen is ever formed, only 7- male; and 
that those derived from 9+7 unions produce 7- and 9- female, and 
only 7- male gametes. 
Returning to the case of 0. semilata de Vries, de Vries states ('09, 
Vol. I, p. 359) that he selfed one of these mutants and obtained 276 
offspring. Of this number, 3 were 0. nanella and 4 0. lata. ''The 
remaining plants clearly exhibited the characters of semilata and 
justify the establishment of this form as a constant species." He also 
pollinated 0. lata with this semilata plant and obtained 105 seedlings, 
39 of which were O. lata, i 0. albida, 61 0. Lamarckiana, 2 0. nanella 
and 2 0. ohlonga (the first two types having 15, the second two 14, and 
the fifth, 14 or 15 chromosomes). ''These forms," he adds, "and the 
proportions in which they occur are the same as those which 0. lata 
produces when crossed with other species" (meaning, probably, when 
O. lata is pollinated with 14-chromosome species, since sufihcient pollen 
