554 Prof. G. Klebs, Alterations in Development and [June 25, 



than in the white. Indeed, a certain formation of flowers takes place in the 

 red light, but it is less than the normal one. On the other hand, the 

 lengthening of the stem and of the flowering branches is exceptionally 

 favoured, so that the appearance of the whole plant is sometimes very 

 abnormal. 



These experiments prove that the transformation of a plant, ripe to flower, 

 into a vegetative one is possible on the one hand by means of an increase of 

 temperature and manure (that is to say, of inorganic salts), and, on the other 

 hand, by means of a deci'ease of carbon assimilation. We find, in this 

 respect, full conformity with tlie behaviour of the lower green plants. 



The whole process of formation of the inflorescence consists of numerous 

 successive stages, of which we will distinguish only three essential ones ; 

 firstly, the lengthening of the axis; secondly, ramification; and thirdly, the 

 genesis of flowers. What we desire to know is whether these stages can be 

 separated from one another as though they were entirely independent. We 

 have just shown that the lengthening of a plant, ripe to flower, can take 

 place without necessarily bringing on ' the other stages. As a rule, the 

 lengthening is a life-process which is connected with the flowering only in 

 the ordinary conditions of life, but it is, in itself, wholly independent of it. 

 All rosettes, the vegetative ones included, can lengthen in darkness ; however, 

 they do so better in the blue ligiit and best of all in the red light. 

 According to the nutritive state of the rosettes and the intensity of the red 

 light the plants cultivated therein obtain different forms. The very young 

 buds springing from the mother plant preserve their character as runners as 

 long as they grow in red liglit and never develop into rosettes. After some 

 time in normal light they can produce new rosettes, not only on the apex but 

 also at other places, an occurrence never to be observed in nature. 



While on the one hand a lengthening without flowering can be attained, it 

 is poHsilde on the other hand to cause a flowering without lengthening. 

 When rosettes ripe to flower are cultivated at the end of April in very warm 

 soil and in strong light, the flowers are developed at the top of the old 

 rosette, without the axis lengthening. 



Under ordinary conditions, the lengthened axis of the inflorescence 

 produces from three to five flowering brandies. The number of these 

 branches and of the ll()W(>r.s can vary in a higli degree, for e.\ani])le when 

 cultivated in a refrigeratoi- nil the l)ranches are suppressed and the 

 inflorescence bears a single ilower. With a very vigorously fed ])lant we 

 observe the production of numerous branches and flowers. In this case the 

 flowering bniiuslKis jjroceedcd not mily tVom th(.> iixils of Mic highest leaves 

 near the apex hut also from tlmsc of tlic niiddh; leaves. The general 



