248 CONSERVATIVE ORGANS. [~LECT. V I 



original trunk sending off two distinct kinds of 

 branches : those at the summit bear leaves and 

 the fructification, while the lower are leafless, 

 and bend down until they touch the ground, in 

 which they root, and are changed into real stems. 

 4. CLIMBING STEMS (scandentes) are those 

 which, being too delicate and flexible to support 

 themselves, require the aid of some perpendi- 

 cular body to enable them to elevate their foliage 

 and fructification in the air ; and this is accom- 

 plished by one or other of the following means : 

 A stem is denominated 



a. Twining (volubilis), when it winds itself 

 spirally round any other plant or upright slen- 

 der body*. This motion is performed inva- 

 riably in one direction by all the plants of the 

 same species ; and is so natural to them, that if 

 it be forcibly reversed, the plants will untwine 

 themselves, and again assume the direction 

 peculiar to their species. When the twining is 

 from left to right, or following the apparent 

 motion of the sun, as in Woodbine, Loni- 

 cera Periclymenwn ; or the Hop, Humulus 



* " Volubilis spiraliter adscendens per ramum alienum. 



" Sinistrorsum ([ secundum solem vulgo: Humulus y 

 " Helxine, Lonicera, Tamus. 



" Dextrorsum D contra motum soils vulgi ; Convolvulus, 

 11 Basella, Phaseolus, Cynanche, Euphorbia) Eupatorium." Phil, 

 Sot. 82. 5. 



