69 
hevbrid abcdefgh ye tae 
, ABCDEFGHIJKLMN 
Since either a or A can enter into any pollen grain or ovule, 
combined with b or B, c or C, and so forth to n or N, as already 
stated, the possible kinds of reproductive cells possible in this first 
generation hybrid X are 2** = 16,384. But when two such re- 
productive cells unite, in fertilization, then the twenty-eight re- 
sulting chromosomes entering into the seed, and so carried into 
the second generation, may consist of a and a (aa), a and A (aA), 
A and a (Aa), or A and A (AA). Since aA and Aa are made up 
of the same constituents, they will be the same in result, so there 
are really three possibilities for the first or a chromosomes: aa, 
aA and AA. Similarly for the second or b chromosomes there are 
three possibilities, bb, bB, and BB, and so on for all of the others. 
the number of possibilities of different combinations of twenty- 
eight chromosomes made up from two each of the fourteen sets 
of two, is (3)1*, or 4,792,869. 
This means there are 4,792,869 possible different seedlings 
that might arise in the second generation from a cross between 
two different gladiolus species, if the two species differ from each 
other in at least fourteen characters, at least one of which is car- 
ried by each of the fourteen chromosomes. Whether any two 
species differ from one another to this degree is not easily proven, 
but garden hybrids seem to, so the 4,792,869 different progeny 
from a single cross are entirely reasonable. 
If we go one step further, and, instead of intercrossing the 
seedlings of one interspecific cross among themselves, we cross 
two interspecific hybrids, each from entirely distinct species, SO 
that in all, four distinct species enter into the heritage of the sec- 
ond generation, then the situation may be depicted by represent- 
ing the chromosomes of the first second interspecific hybrid by 
letters and by numerals thus: 
Se bt diet eg ey Ee o 
 \ncpERGHiI}eueN 
mg t' 23 45678 9 10 11 12 13 14 
tr IL III IV V VI VII VIII IX X XI XII XIII XIV 
