116 CLIMBING PLANTS. 



This expresses very prettily a thing which every 

 garden-lover must have noticed, that a vine will 

 find out its support anywhere within a reasonable 

 distance. Of course, the choice between the trellis 

 and the pole is a genial fancy of the gardener ; 

 but it is a fact that a plant with tendrils will 

 find out and clasp a stick placed at a short dis- 

 tance from it on any side, and, similarly, that 

 a Morning-Glory will wind about a pole in its 

 neighborhood, on whichever side this may happen 

 to be. The explanation of this curious phenome- 

 non was sought and found by Charles Darwin, 

 and he was led to study the subject in the follow- 

 ing way. 



In August, 1858, Dr. Gray read a short " Note 

 on the Coiling of Tendrils " before the American 

 Academy of Arts and Sciences. 1 In this paper he 

 spoke of the views of a German, Hugo von Mohl, 

 who had published a book on the subject twenty 

 years before. 2 Von Mohl said that the coiling was 

 due to an irritability excited by contact, that it 

 was of the same nature as the closing of the leaves 

 of the Sensitive Plant at the touch. Dr. Gray 



1 "Proe. Amer. Acad. of Arts and Sciences." 1858. 



2 "Ueber das Bau und das Winden der Ranken und Schlingpflan- 

 zen." 1827. 



