MUTATION 313 



cisive observations and to formulate certain general 

 rules or laws. 



CEnothera was introduced from America on several 

 occasions into European gardens; it also grows wild, 

 escaping cultivation, and several species of it have 

 been listed. The one De Vries selected for his ex- 

 periments is known as lamarchiana for the reason 

 that Lamarck first described it after observing it in 

 the garden of the Paris Museum where it was culti- 

 vated. 



"This striking species was found in a locality near 

 Hilversum, in the vicinity of Amsterdam, where it 

 grew in some thousands of individuals. The first 

 discovery of this locality was in 1886. This plant 

 showed the long-sought peculiarity of producing a 

 number of new species every year. Some of them 

 were observed directly on the field, either as stems or 

 as rosettes. The latter could be transplanted into my 

 garden for further observation, and the stems yielded 

 seeds to be sown under like control." 



"Lamarck's evening-primrose is a stately plant, 

 with a stout stem, attaining often a height of 1.6 

 meters and more. The main stem is surrounded by a 

 large circle of smaller branches, growing upwards 

 from its base so as often to form a dense bush. The 

 flowers are large and of a bright yellow color; they 

 open towards evening, as the name indicates." 

 The new species produced were O. gigas, O. rubriner- 



