DO 
llll': ORIHID WORLD. 
( I)cCL-ml)cr, lyi 
years ago, there can be no doubt that the 
rosy-purple colour present in the flowers and 
leaves of the various species of Cattleya and 
Cypripedium is due to the simultaneous 
presence of two complementary colour factors 
which we call C and R. If one or both of 
these factors is absent, the result is a true 
albino, with no trace of purple saji m the 
flowers and leaves. This purple colour can 
only be produced when the two factors C and 
R are both present. 
Now as we have just seen, the colour 
factors C and R may be present in a double 
state, CC and RR, or in a single state, Cc and 
Rr, or they may be absent altogether, cc and 
rr, consequently no less than five different 
kinds of albinos may exist, as follows: — 
(0 CCrr (3) ccRR 
(2) Ccrr (4) ccRr 
(5) ccrr 
For the sake of convenience, it is usual in 
genetics to represent the presence of a factor 
by a capital letter and its absence by a small 
one. 
These five albinos may be absolutely iden- 
tical in appearance and outward characters, 
yet each has a different germinal constitution, 
and consequently will give different results in 
breeding. Each of these five albinos will 
breed true to albinism when selfed, but when 
they are crossed inter sc different results will 
be obtained. Thus, out of the 1 5 possible 
matings 11 will give all albinos; 2 will give 
on the average equal numbers of albinos and 
coloured forms ; i will give I coloured form 
to 3 albinos ; and i v-'ill give all coloured 
forms. 
Table I gives the factorial details of these 
1 5 matings, showing how the above calcula- 
tions have been made. 
Tahle I. (Albino Matings.) 
Parents. Offspriiif^. Result. 
(I) CCrr X (I) CCri- all CCrr all Albinos 
(I) CCrr X (2) Ccrr i CCrr: 1 Ccrr all .\lhinos 
(I) CCrr X (3) ccRK all CcRr all Coloured 
( I Coloured: 
(i) CCrr X (4) ccRr i CcRr: i Ccrr \ , Albino 
(1) CCrr X (5) ccrr all Ccrr all Albinos 
(2) Ccrr X (2) Ccrr { ' ^Cn;: 2 Ccrr: j ^„ 
^ 7, ( 1 Coloured : 
(2) Ccrr X (3) ccRR i CcRr: i ccRr j , Albino 
Offspring. 
1 CcRr : i ccRr: 
I Ccrr : i ccrr 
1 Ccrr : i ccrr 
all ccRR 
I ccRR : I ccRr 
all ccRr 
I ccKR: 2 ccRr: 
1 ccrr 
I ccRr : i ccrr 
all ccrr 
Result. 
J I Coloured: 
( 3 Albinos 
all Albinos 
all Albinos 
all Albinos 
all Albinos 
all Albinos 
all Albinos 
all Albinos 
Parents. 
(2) Ccrr X (4) ccRr 
( 1) Ccrr X (5) ccrr 
(3) ccRRx (3) ccRR 
(3) ccRRx (4) ccRr 
(3) ccRR x (S) ccrr 
(4) ccRr X (4) ccRr 
(4) ccRr X 15) ccrr 
( 5 ) ccrr X ( 5 ) ccrr 
C represents ist colour factor. 
R represents 2nd colour factor. 
CC and RR represent double presence of 
factors C and R, i.e., homozygous, or pure. 
Cc and Rr represent single presence of 
factors C and R, i.e., heterozygous, or impure. 
cc and rr represent absence of factors C 
and R, i.e., zerozygous, or lacking. 
The same scheme, of course, applies equally 
to coloured forms as to albinos. Thus, four 
distinct kinds of coloured forms are possible, 
viz. : — 
(a) CCRR (c) CcRR 
(b) CCRr (d) CcRr 
These four coloured forms may be absolutely 
identical in appearance and outward char- 
ricters, yet each has a different germinal con- 
stitution and consequently will give different 
results in breeding. Of the 10 possible 
matings 5 will give all coloured forms ; 4 will 
give on the average 3 coloured forms to 
I albino ; and i will gi\'e on the average g 
coloured forms to 7 albinos. 
Table II. gives the factorial details of these 
matings, showing how the above calculations 
have been made. 
Table II. (Coloured Matings.) 
l^arenls. Offspring. Result, 
(a) CCRR X (a) CCRR all CCRR all Coloured 
(a) CCRR X (b)CCRr i CCRR: i CCRr all Coloured 
(a) CCRR X (c) CcRR i CCRR : i CcRR all Coloured 
r^r■^-,^~> / i , 13 I I CCRR : I CCRr ■ 
(a) CCRRx(d)CcRr, , CcRr 
(b) CCRr X (b) CCRr { 2 CCRr 
I 1 CCRR: 1 CCRr 
(b)CCRrx(c)CcRR) , c^j^j^. , ^^^j^^ 
, r-n. , r u ^ i rrp^' ' ^r^f ' \ ^ Coloured 
( b ) CCRr x ( d ) CcRr ^ 2 CCRr : 2 CcRr : ^ .^j^j^^^ 
1 CCrr : i Ccrr ) 
iCcRR: \ 3 Coloured 
< I Albino 
I CCRR : I CCRr 
(c) CcRR X (d) CcRr \ 2 CcRR : 2 CcRr 
I ccRR : I ccRr 
I CCRR : 2 CcRR 
I ccRR : 2 CCRr 
(d) CcRr X (d)CcRrj4 CcRr : 2 ccRr 
1 CCrr : 2 Ccrr 
■ I ccrr 
all Coloured 
(c)CcRR X (oCcRR \ ;CCH1> 
/ 3 Coloured : 
1 I Albino 
( all Coloured 
6 Coloured : 
2 Albinos 
9 Coloured : 
7 Albinos 
