84 
THE ORCHID WORLD. 
[January, 1913. 
kinds of blotching. The plam form of O. 
crispum is, of course, often shghtly spotted, 
especially on the lip. The yellow ground 
colour in Odontoglossums varies considerably 
in shade according to the species and variety 
used. Some of the bright yellow species are 
evidently heterozygous, carrymg cream reces- 
sive, as may be seen in some of the Fi results 
of yellow X white in certain primary hybrids 
where segregation into the two distinct 
shades, cream and canary-yellow, is evident. 
When a pure white ground appears in Fi 
results of yellow x white, it is evidently due 
to the heterozygous nature of the wild yellow 
form used as a parent. 
The Making of a Scarlet Crispum. 
A large number of interesting problems 
have already been taken ni hand by Orchid 
breeders, some of which bid fair soon to be 
successful, though, to the student of genetics, 
the results seem to be slow in coming to hand. 
The question, for instance, of the making 
of a Scarlet Crispum by combining the self 
scarlet colour of Cochlioda Noetzliana with 
the large size of Odontoglossum crispum. 
The making of a Scarlet Cattleya by com- 
bining the scarlet self colour of Sophronitis 
grandiflora with the large size and broad seg- 
ments of the species of the labiata group of 
Cattleya. The making of a Yellow Cattleya 
by combining the yellow self colour of Laelia 
Cowanii with the large size and broad seg- 
ments of the Cattleya. These and other 
problems equally interesting to Orchid 
breeders are, judging by the results recently 
presented, now well on the way to a solution. 
There is no doubt that the application of 
the principles of genetics to these problems 
would not only help to hasten their solution, 
but would also save much wastage of 
mistaken matings. In the three particular 
problems noted above, the first crosses in Fi 
all show a more or less incomplete dominance, 
both of the desired colour and size characters. 
In other words, the single dose of each factor 
present in the primary hybrid gives a different 
result from the double dose of each factor 
present in the pure parents. Thus the double 
dose of the factor present in the Cochlioda. 
Sophronitis, and Laelia parents, produces the 
scarlet or yellow colour to perfection, whereas 
the single dose only of the factor present m 
the primary hybrids reproduces the scarlet or 
yellow colour more or less imperfectly. 
The same thing happens in regard to the 
factor for size. The double dose of the factor 
present in the Odontoglossum and the Catt- 
leya parents produces the large size desired, 
whereas the single dose only of the factor 
present in the primary hybrids does not The 
simple solution of the problem, therefore, lies 
in choosing the particular matings that will 
give a double dose of each of the two char- 
acters that the Orchid breeder wishes to com- 
bine, in these cases the scarlet or yellow 
colour and the large size. It is obvious that 
this can be done simply by mating two of the 
Fi hybrids together, and if the case is a simple 
one, the desired result should be secured in 
Fa, on the average in one plant out of every 
sixteen raised. 
From this it will be seen that the common 
practice of mating the primary hybrid back 
to one of its parents cannot be expected to 
succeed, because such a mating implies the 
presence of a single dose only of one of the 
two characters concerned. By such a mating 
one of the characters is secured by a double 
dose at the expense of the other which can 
only have a single dose. Further, the many 
attempts that have been made to secure the 
result by breeding from secondary and other 
complex hybrids only leads to unnecessary 
complications, because owing to segregation 
it is quite possible to lose the desired factor 
altogether in the second generation F2, and 
the securing of a double dose of it by means 
of such matings is a matter of considerable 
uncertainty, with the chances very much 
against the breeder. 
In passing it may, perhaps, be useful to 
point out that the common practice of 
analysing Orchid hybrids of complex parent- 
age in terms of fractions of their parents and 
ancestors is to be deprecated. In Orchid 
literature we often see it stated, for instance, 
that a certain hybrid contains ^A, ^B, jC and 
iD. In the modern light of genetics such 
statements are not only misleading, but in 
