266 The Pedigree Families. 



them with their own pollen. They have since that time 

 bred true and given rise to no more 0. Lainarckiana; 

 nor have they, since that time given rise to any muta- 

 tions. 



How and when O. laevifolia arose I do not of course 

 know. It was already there when I visited the locality 

 for the first time. But it grew there in a special isolated 

 spot in such a way as to make it probable that the plants 

 had grown from the seeds of a single parent which we 

 must suppose had arisen there not so very long before. 

 I propose, therefore, to give a somewhat detailed de- 

 scription of the original locality. I shall have frequent 

 occasion, when I shall be describing other families or 

 individual species, of referring to it again. 



■■ On the estate of Jagtlust, the property of Dr. juris 

 J. Six, between Hilversum and 's Graveland in the 

 Netherland province of North Holland there was at one 

 time a potato field, whose southern boundary bordered 

 on a canal which had been dug many years before. About 

 the year 1870 the owner had a new branch of this canal 

 dug which followed the western boundary of the field, 

 and completely shut off any access to it from the north. 

 So that the field became accessible only from the east 

 where there was no road ; and it consequently became im- 

 possible to let it. From that time it lay fallow; and in 

 the first few years was not dug any more than was neces- 

 sary for the laying of a few paths and the planting of 

 a few trees. It obviously afforded wild plants a splendid 

 opportunity of almost unlimited multiplication. Oeno- 

 thera had seized this opportunity somewhat later than the 

 other wild plants in the neighborhood and although it 

 did not spread as fast as they, it took fuller advantage 

 of the field in the end. 



