222 WINTERING HABITS [ch. 



lines. These turions were regarded as a definite adaptation 

 devised by the plant to tide over the cold season, and to ensure 

 vegetative propagation. But this position has been undermined 

 by experimental work originating with Goebel's^ discovery 

 that turion formation in Myriophyllum verticillatum is definitely 

 the result of unfavourable conditions. This observer, for ex- 

 ample, placed some of the buds in a glass vessel with water but 

 without earth, where they grew into richly rooted plants, more 

 than 30 cms. long. By April i, these plants had all formed 

 new turions terminating the main and lateral shoots, while in 

 the locality from which the original winter-buds had been 

 collected, their contemporaries remained still ungerminated! 



Fig. 145. Myriophyllum verticillatum, L. One of the turions shown in Fig. 144, 

 p. 221, which had begun to germinate after the winter's rest and was found at the 

 bottom of the water in this condition on March 16, 1912 ; h, base. (Nat. size.) [A. A.] 



Gliick^, who has carried Goebel's work on Myriophyllum fur- 

 ther, has shown that if the plant is grown in a vessel of water, 

 over-crowded with other aquatics so that there is much com- 

 petition for food, 'winter' bud formation may occur even in 

 the spring. He also planted turions of M. verticillatum in soil, 

 and cultivated them for an entire summer as land plants. 

 Numerous green shoots were formed, but, by the beginning of 

 August, each individual plant had also produced four to ten 

 pale green turions (Fig. 146 X), most of which were under the 

 soil. This early development of turions is attributed by Gluck to 

 the lack of water from which the plants suffered. On the other 



1 Goebel, K. (1891-1893). 2 Gluck, H. (1906). 



