( 811 ) 



may exist of one and tlic same Umbellifer and other related questions 

 can only be obtained by culture experiments and statistical investi- 

 gation. 



Yet I thought it wortli while to communicate these observations 

 although they must only be considered as an exposition of the 

 grounds why culture experiments were undertaken. It may be useful 

 to indicate these grounds, first because they support my conception 

 about the racial character of many cleistogaraic plants, and further 

 because in my opinion we may certainly expect that besides monoe- 

 cious and cleistogamic plants, other plants in the natural state will 

 turn out to have the character of races originated by mutation, so 

 that this communication may to some extent draw attention to this 

 point. 



The culture experimejits will from the nature of the case occupy 

 a few years. 



In the Erganzungsband of Flora J 905, Heft I, p, 214, Gokbel 

 communicates as a sequel to his paper "Die kleistogamen Bliiten 

 und die Anpassungstheorien" the results of his continued culture 

 experiments with cleistogamic species of Viola. The results of his 

 experiments confirm his formerly pronounced opinion that the appea- 

 rance of a cleistogamic or chasmogamic flower depends entirely 

 on nutritive conditions. If these are favourable the chasmogamic 

 flower is seen to appear; in the opposite case the cleistogamic one 

 appears. 



I communicated in my former article my objections to this con- 

 ception. I will now only remark that the influence of the nutritive 

 conditions shows itself in such a way that with favourable conditions 

 the .semi-latent character is developed, and with unfavourable is 

 suppressed. 



Now if in Goebel's experiments the chasmogamic flowei-ing is 

 suppressed when the plant is under unfavourable conditions, this is 

 because Viola is an ever-sporting variety in which the chasmogamic 

 flower is in a semi-latent condition. If the cleistogamic Viola be- 

 longed to one of the other ever-sporting varieties, if e.g. it were 

 an ever-sporting variety like the gyno-monoecious form of Satureja 

 horten.üs or Trifolium pratense quinquefolium in which the anomaly: 

 (the female flower and the composite leaf) is in a semi-latent con- 

 dition, then under favourable nutritive conditions the anomaly, the 

 cleistogamic flower and under less favourable conditions the chas- 

 moijamic flower would be fostered. 



