THE MUTATIONS OF OENOTHERA STENOMERES 
103 
lasiopetala between 40 and 50 per cent are perfect., the remainder 
shrivelled and defective. 
The Fi progeny of mut. lasiopetala, from self-pollinated seeds of 
no. 32-4-6-15, may be summarized as follows: 
Seeds 
Plants 
F. typica 
Mut. lasiopetala 
Other mats. 
78 
26 
Capsule B 
122 
39 
51 
Total Fi 
116 
70 
44 
2 
The progeny consisted of 60 per cent, f . typica and 40 per cent. mut. 
lasiopetala. The two types were distinguished at a very early age. 
The mode of inheritance is comparable to that of two of the mutations 
from Oe. Lamarckiana Hort. namely Oe. lata de Vries and Oe. scintillans 
de Viies. The former is generally self-sterile for the reason that it 
produces no good pollen: de Vries, ^ however, succeeded in deriving a 
fertile strain from the cross Oe. lataXsemilata, and found that its 
progeny by self-pollination consisted of Oe. lata and Oe. Lamarckiana ^ 
just as would have been the case if the pollen had been derived from 
Oe. Lamarckiana. In other words, it appears that the good pollen 
grains of Oe. lata are genetically the same as those of Oe. Lamarckiana, 
and do not carry the /ato-characters. This conclusion is borne out by 
the fact that lata-Vike fertile hybrids between Oe. lata de Vries and 
Oe. Hookeri T. & G. cannot transmit the /a/a-characters through the 
pollen, and transmit to only a portion of their progeny through the 
eggs. Oe. scintillans acts like Oe. lata in everyway ; its pollen, moreover, 
is always sufificient for self-pollination. 
Thus it appears that there is a class of mutations of which the eggs 
are of two kinds; one kind carries the characters of the parent species, 
the other kind the characters of the mutation. The pollen grains, 
however, appear to be of one kind only, and to carry the characters of 
the parent species. Is it not possible that the male gametes which 
carry the characters of the mutation are eliminated because of some 
physiological defect? If so, Oe. lata might be supposed to originate 
by the union of a lata-egg (itself constituting the true mutation) with 
a Lamar ckiana-sperm. Then Oe. lata would be a heterozygote, and 
would produce gametes of two kinds. If the male lata-gametes were 
eliminated, the progeny of Oe. lata would consist of both Oe. lata and 
^ Gruppenweise Artbildung, p. 256. 
