Influence of Extenial Conditions on Tricotyly. 453 



HEREDITARY VALUES IN OENOTHERA HIRTELLA IN 1899. 



Percentage values 10 20 30 40 50 60 70 80 90 



After manuringf with nitrates 8 17 12 9 5 2 2 1 

 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 

 Helichrysuni bracfeafuni. 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 IN 1899. 



Percentage values 10 20 30 40 50 Mean 



After manuring with nitrates 2 22 18 5 1 26% 



After manuring with phosphates 1 5 20 11 2 32% 



Number of individuals 48 and 39. The grow tli 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, onh' 39 (^f the 

 50 plants which had been set out set sufficient seed. 



Results as definite as these are not, however, always 

 obtained, especially when a comparison is instituted not 

 between individual plants raised from seed, but between 

 the various parts of a single individual obtained bv di- 

 viding it. I conducted such an experiment with Oeno- 



