The Laez'ifolia-Fainil\. 271 



my new species it was not until many years had elapsed 

 that I succeeded in getting them to flower and ripen their 

 fruits — as for example O. albida and O. elliptica. 



I must now return to O. laevifolia. I found it first 

 in 1887 when I came across ten specimens which coukl 

 be recognized as a new type by the oval, as opposed to 

 heart-shaped, petals of the flowers of their lateral 

 branches. 



Five of these plants formed the nucleus of a little 

 group of about a hundred individuals which stood in the 

 northwest part of the field far removed from any other 

 Oenotheras. In the previous year I had seen on this spot 

 some first year's rosettes, but no flowering plants. At 

 greater and lesser distances from this center there grew 

 five other plants in rather isolated positions in the field 

 which was still poor in Oenotheras in this region. 



In the following year I found this type in the same 

 spot but not elsewhere. 



Since that time 0. laevifolia has maintained itself 

 on the field in such a way that the original spot, which 

 was easily recognizable by certain features, has continued 

 to form the nucleus of the whole group. In subsequent 

 years I have found the species in other parts of the field 

 also — but as rare and isolated examples only. The num- 

 bers of it, however, on the original spot have graduall\- 

 if slowly increased; the group consists, doubtless as the 

 result of mixed fertilization by insects, partly of 0. 

 laevifolia and partly of O. Lainarckiana. Since 1894 

 that part of the field has been completely overgrown with 

 Oenotheras so that the limits of the original group have 

 disappeared. 



This m.ode of distribution of our plant round a defi- 

 nite center for a period of eight years coupled with the 



