APPENDAGES OF THE STEM. 157 



Tendrils. Are tortuous processes produced by- 

 weak stemmed plants to enable them to cling to, 

 and support themselves on other plants or bodies in 

 the air. Some are produced from the wood, and are 

 permanent, though they lose vitality in the second 

 year, as the grape vine. In this last-named tree, 

 the first two, three, or four tendrils at the bottom of 

 the shoots, are the common peduncles of the thyrse 

 of flowers if they receive the requisite supplies of 

 air, light, and heat ; but if these elements be wanting, 

 the flowers are imperfect and abortive : of course the 

 peduncle is resolved into a barren tendril. Every 

 plant that is furnished with such members shows its 

 climbing character, and that it is not intended by 

 nature to grovel on the ground. Some climbers 

 support themselves by the reflexed position, or 

 twisting character of their petioles, and others by 

 the paw- like form and insinuating processes of their 

 clinging fibres* Spiral tendrils convolve first one 

 way for about half their length, and afterwards the 

 contrary way. 



Glands. Are small protuberances seated on va- 

 rious parts of plants. They appear to be either 

 secretory or excretory organs. Root fibres are 

 observed to proceed from them in the case of layers* 

 Those on the petioles are particularly conspicuous, 

 and from their form only, it has been conceived they 

 indicate a peculiar character of hardihood, or a cer- 

 tain susceptibility of the plant to suffer under, or 

 resist, certain influences of the atmosphere. On the 



