440 BOTANICAL GAZETTE .- [DECEMBER 
among 118 plantsof the cross. Asa matter of fact, the significance 
of ratios in Oenothera can be maintained only with great caution, 
in view of the enormous elimination of gametes during matura- 
tion and the subsequent failure of large classes of zygotes to 
develop. Nevertheless, the absence or almost complete absence 
of a strong zygote such as f. ¢ypica in the progenies of mut. angusti- 
folia and mut. angustifoliaXf. typica is strong evidence for the view 
that the composition of the progeny among the mass mutating 
strains is conditioned by the female gametes. The failure of a 
TABLE IV 
ANALYSIS OF F; CULTURES OF MUT. gianni, LEXINGTON E-5-208, SELF-POLLINATED 
RECIPROCALLY CROSSED WITH F. typica, LEXINGTON E-5-229 (THE 
PLANT WHOSE PROGENY IS ANALYZED IN TABLE III 
The ucmeses was a sister plant of the ¢ypica plant with which it was crossed; for 
n in pedigree see table II, culture 1 from Lexington E-5 
eet ee ee ee eee a| os 
Parent as 3 E oe be a : mutations 3 F 8 E 
7 EI s E4 a & 
te a eae ee a ie 
Mut. angustifolia. .| 651*| 505 | 2 4 2 | 2r | 475 |1(no.1x)| 503 | 99.6 
Mut. angusti - lia 
Xe. typica seat t99{| 173 | © ° 4 | 168 |r (no.1)} 173 |100 
F, typicaXmut. 
angustifolia..... 182t| 118 | 10 re) I 99 4 108 | 9.5 
* The 651 seeds f psules, ini pectively 51, 75, 53, 62, 44, 59, 82, Tor, 46, 33, 
andac 52, 75, 53 
t The 199 seeds were from 3 capsules, containing respectively 73, 47, and 79 seeds. 
t The 182 seeds were from 2 capsules, containing respectively 79 and 103 seeds. 
class of strong zygotes to appear has much greater evidential 
value than any fluctuation in the proportion of weak zygotes. 
From other sources the evidence is unusually strong that the female 
and male gametes of O. pratincola are not equivalent, and that many 
characters are not carried by the male gametes. 
In conclusion: mut. angustifolia ordinarily gives a progeny 
containing nearly 100 per cent of f. typica; in a strain exhibiting 
mass mutation many of the typica plants are replaced by mutations 
of the characteristic group. Presumably other individuals of 
mut. angustifolia could be found which would be less mutable than 
the one tested, just as different individuals of f. typica show widely 
