54 
GENETICS: SETCHELL ET AL. 
Proc. N. A. S. 
contrast to the persistent and at times accrescent nature of the calyces 
of normal forms. This character proved to be a simple recessive. Fi 
was normal except for slight suggestions of a petaloid condition of the 
calyx tips on some of the flowers of the Fi plants. F 2 gave 61 normal: 
35 split hose-in-hose. In F 3 , seven families from F 2 split hose-in-hose 
segregants gave 175 plants all bearing split hose-in-hose flowers. Of 
ten families from normal F 2 segregants two gave only normal descendants, 
while eight exhibited segregation into normal and hose-in-hose in the 
numbers 133 normal: 42 split hose-in-hose. Four F 2 families were ex- 
amined for simultaneous segregation of pink versus red and normal versus 
split hose-in-hose. The results were 109 pink normal : 36 pink hose-in-hose : 
43 red normal: 11 red hose-in-hose, which is in substantial agreement with 
a 9 : 3 : 3 : 1 ratio for independent segregation in these two pairs of 
allelomorphs. The results establish the existence of a single pair of allelo- 
morphs, Cc, for the character contrast normal versus split hose-in-hose 
(calycine) flowers. 
The Alba-Macrophylla Series. — In the alba (White) -macro phylla series 
our attention was largely confined to flower color, alba being white and 
macrophylla, as we have seen, red. The F\ in this case was definitely 
pink, and F 2 gave (combining 1911 and 1916 results) 180 pink: 58 red: 
83 white. This result is in very satisfactory agreement with a 9 pink: 
3 red: 4 white ratio, which may be accounted fo r by adding to the Rr 
pair of allelomorphs previously demonstrated a second pair, Ww, for 
colored versus white flowers. Alba is then RRww, and macrophylla, 
rrWW ; and the F b RrWw, is pink as in the two previous series. Of five 
F 3 families grown from red F 2 segregants, th^ee (rrWW) bred true for red; 
one (rrWw) gave 35 red: 14 white; and one gave the anomalous segrega- 
tion product of 2 red: 23 white. Seven families were grown from pink 
F 2 plants. Five (RrWw) segregated for pink, red, and white in the num- 
bers 73 pink : 25 red : 28 white ; one (RrWW) gave 22 red : 3 pink ; and one 
(RRWw) gave 33 pink: 9 white. Only one pink genotype, RRWW, 
was not demonstrated, but this is not inexplicable in view of the fact that 
only one in nine of the F 2 pink-flowering plants should belong to this geno- 
type. Seven F 3 families were grown from white F 2 segregants. Among 
191 plants, otherwise white-flowering, there was a single pink-flowering 
individual. It was doubtless a stray of some sort. The difference be- 
tween the red flowers of macrophylla and the white ones of alba, therefore, 
finds a satisfactory formulation as a bigenic contrast. 
Discussion of Results. — The results of the flower color studies set forth 
above appear at first sight to conflict with those which have been published 
by Allard. 4 He found that carmine, a color cnly slightly different from 
the red of macrophylla, was a simple dominant to pink ; and when he crossed 
it with white, he obtained Fi lighter than carmine, and an F 2 progeny 
which might have been interpreted as 9 carmine: 3 pink: 4 white. Certain 
