300 Noii-IsokWlc Races. 



capacity to do this is present in them in a semi-latent 

 state. ^ 



With Oenothera Laiiiarckiana I have made some more 

 extensive experiments on accelerating the development of 

 the stem by improving the conditions of growth. In the 

 wild state this plant consists chiefly of biennials, Init 

 partly also of annual and of triennial individuals. Under 

 experimental conditions, however, the duration of its 

 life seems to depend more on external influences than 

 on the choice of seeds. I have especially tested the 

 distance between the plants, the sunniness of the position, 

 and the richness of the soil. 



In 1888 I selected some seeds of my biennial stock 

 plants of the Lamarckiana family of 1886-1887,- in order 

 to investigate the effect of the degree of separation of 

 .he plants in the bed. For this purpose I selected four 

 adjacent beds of similar contents with regard to soil and 

 manure, sowed the seeds in the middle of April fairly 

 thickly in rows, and weeded them out during germina- 

 tion in such a way that on two beds the plants stood at 

 moderate distances, on one fiu'ther apart, and on a 

 third more closely. In the summer up to the middle of 

 September I recorded the number of individuals with 

 stems and the number of the rosettes. The sum of the 

 two obviously affords a measure of the distances between 

 the plants. The extent of each bed was 13 square meters. 

 The figures are : 



"^ Sur la culture des monstruositcs, Comptcs rcndiis de I'Ac. d. 

 Sc, Paris, January, 1899; Sur la culture dcs fasciatious dcs cspcccs 

 annuclles et bisannuelles, Revne generalc de botanique, Vol. XT. 

 1899, P- 136; and Ueher die Abhangigkeit dcr Fasciation vom Alter 

 hei sweijdhrigen Piianzen, Botanisches Centralblatt, Vol. LXXVII, 

 1899. 



' See the pedigree in Vol. T, p. 224. 



