Influence of External Conditions on Tricotyly. 453 
HEREDITARY VALUES IN OENOTHERA HIRTELLA IN 1899. 
Percentage values 10 20 30 40 50 60 70 80 90 
After manuring with nitrates 08 17 12 95221 
After manuring with phosphates 129 14 78511 
The number of individuals in the first experiment is 
56, in the second 48; average harvest per plant, 3.5 and 
2.5 cc. The seed was collected from the terminal spike 
only. The mean value for the nitrate plants was 37%, 
for those manured with phosphates, 44%. The parent 
of all these plants had had a value of 66%. 
Manuring with superphosphate has therefore, in this 
case, in an otherwise uniform culture, been more favor- 
able to the production of tricotylous seedlings than ma- 
nuring with hornmeal. 
I found exactly the same result in the same year with 
Helichrysum bracteatuni. I planted out tricotylous seed- 
lings only of a single parent with 11%. I determined and 
arranged the values as before and found : 
HEREDITARY VALUES IN HELICHRYSUM BRACTEATUM IX 1899. 
Percentage values 10 20 30 40 50 Mean 
After manuring Avith nitrates 2 22 18 5 1 26% 
After manuring with phosphates 1 5 20 11 2 32% 
Number of individuals 48 and 39. The growth on 
the nitrate bed was very luxuriant ; the leaves were dark- 
green, and the flowers abundant. On the phosphate bed 
the plants were yellowish-green, very little branched, and 
with fewer ripe flowerheads. Indeed, only 39 of the 
50 plants which had been set out set sufficient seed. 
Results as definite as these are not, however, always 
J 
obtained, especially when a comparison is instituted not 
between individual plants raised from seed, but between 
the various parts of a single individual obtained by di- 
viding it. I conducted such an experiment with Ocno- 
